Everyone else has had one of these self aggrandizing threads, and some people have had half a dozen or more, so its my turn to have just one. 
Below are miscellaneous thoughts, criticisms, and predictions about areas of 4e. They are in almost no particular order.
Character classes I've seen in use:
Fighter, Maul
In spite of early concerns that this character wouldn't be durable enough to perform as a defender, he's done just fine. The high damage of his weapon helps make his class abilities more effective, and he's chosen powers that help him regain hp. The complete lack of any armor check penalty has been a quiet MVP for this character, since he can climb and jump better than anyone in the group. This enhances his mobility in unexpected ways, and gives his player a thrill.
He chews up a lot of healing surges, but he has 11.
Cleric, Laser
Temporary hit points on tap seems to be the best option here. I think this player would drop Lance of Faith in an instant if there were more at wills available, since its damage isn't that much different from Radiant Surge. Daily powers are incredible. Not a lot to say overall, though- about what I expected from a cleric.
Healing Lore could be reworded to clarify how it works with continual healing and with healing from paragon path abilities or cleric only feats. Its text is unambiguous, but seems not to match the intent.
Rogue, Brutal, Rapier (rethemed as katana for extra fun)
Its odd, but this character's encounter and daily powers are rarely used. I think they're going to get switched out soon. See, so much of their damage comes from sneak attack that switching to a more damaging power just isn't that useful- and if you have to attack AC instead of Reflex, it may even be counterproductive. So I think the way to go here is to use encounter and daily powers for effects, not for damage.
This class is frontloaded, big time, especially with a human brutal rogue, Backstabber feat, Nimble Blade, and Piercing Strike. Xavier's attack against a flanked foe was +10 v ref, 3d8+6 damage, at level 1. I don't think it breaks the game, but I think you can definitely see a change from overpowered to balanced as the game progresses from level 1 towards level 10.
He doesn't do well without allies to help him flank. I am reminded of multiple times that single goblins, below his level, have beaten him down. Its become a running joke.
Ranger, Two Bastard Swords
This character gets herself into trouble a lot. She's highly mobile, and can move amongst her foes easily, so she uses that ability to flank with the Fighter. And then she gets flanked too, and takes a lot of damage. She probably takes more damage than any other character in the party. But she's still alive, so I guess that's ok.
Twin Strike, coupled with Hunter's Quarry, creates an oddly consistent damage output for a Striker. Her peak damage doesn't tend to be as high as that of the rogue, and sometimes I think she wishes it were higher, but I'm pretty sure that if we added up total damage per combat she'd be tied or ahead. She also occasionally feels bad because her daily powers promise her so much damage, but they also require multiple attack rolls, at least one of which always misses, basically guaranteeing that she never actually gets as much of the promised damage as she was led to expect.
I probably should funnel her better weapons. I think she's behind, due to the difficulty of getting two identical bastard swords into the game while using modules. I'll look into that.
Wizard, Orb, Fire Magic
Some people complain about the wizard, but I've never noticed a problem in our group. Our wizard's damage output is quite adequate. Fireball and Shroud of Fire account for an awful lot of pain per encounter. Fireball is responsible for our Highest Damage Attack Ever- almost 60 damage with a single attack at level 5. And it could have easily gone a lot higher- there were only four targets in the blast at the time, and the damage rolled wasn't particularly high.
The fact that Cloud of Daggers auto-kills minions seems like a glitch to me.
Warlock, Fey Pact
I think this class gets a slow start. Also, its really hard to use to full effect. Basically, you have to arrange things so that enemies die at choice moments and power you to complete your master plans. This rocks when it works, but has the potential to go very wrong.
Also, some of the early powers seem underpowered. I mean, Charisma v AC? Seriously?
Looking ahead, I don't think this will be a problem long term. But at least for the fey pact, the damage is low. The action denial is crazy good, mind you, particularly once you hit paragon tier. Like, seriously, crazy good. This is probably one of the best characters to have around when facing a solo or an elite. Not... not really a striker though? A different pact seems like it would be more striker-ish, given that the other two pact at wills can potentially deal almost twice as much damage. And they still have a bit of control in them, for that matter.
Teleporting infinitely is cool, but eventually less useful than you might want. You know, after the second or third time you've teleported in a single round. The feat that grants a second pact should be a help here, so she can alternate between teleporting and gaining temporary hit points.
Nothing on the warlord or paladin, sorry. Haven't seen them in use.
General comments on other matters.
Items
I would have preferred even fewer item slots, but whatever. Everyone else in the world but me loves their l3wt. I can't complain much if incredibly popular aspects of the game haven't been fit to my personal preferences.
Multiclassing
I love the multiclassing system, sort of. I love the idea of dipping by means of a feat into the abilities of other classes. I disagree strenuously with those who feel this isn't "true" multiclassing. Its true enough for me. If I can play a smart guy in heavy armor with a sword who can also toss a fireball or two, I feel pretty darn multiclassed.
The problems I have are thus- to multiclass well, you need the following: 1. A strong stat of the appropriate type that you can increase as you level. 2. Usually a strong weapon or implement of the relevant type. 3. A third arm to hold that implement. The last one presents the greatest difficulty. This is a patchable problem, but it is an issue.
Strategy
I suck at predicting low defenses now. I haven't figured out if this is the system or just me, dealing with a new paradigm. When I DM, I make sure to give my players feedback on this subject, and to describe monsters in a way that will suggest to them the best approach.
Minions
Mixed opinions here. I love the idea of minions. But the specific minion rules they've used, coupled with certain powers, give me a sense of disconnect. Cloud of Daggers auto kills minions by leaving them stuck in a zone that does about two damage when used by our wizard. But Reaping Strike, which automatically does at least 4 damage when used by our fighter, doesn't auto kill a minion. Slashing Wake auto kills minions, but Fireball doesn't. I'd like some consistency, and beyond that, I'm not sure that a minion should ever be automatically killed at all.
Plus, minions devalue at higher levels. I don't know enough about higher level play to know whether this is factored in. It could be, honestly, it would be pretty easy to do. But I haven't checked.
The reason minions devalue is because area of effect attacks are more common and more precise. At level 11 our party will have a cleric who can drop a per encounter close burst 8 that damages only enemies, and our wizard will be able to do multiple similar attacks. That basically means that the first round of combat will kill about 75% of the minions present, while still dealing acceptable damage to the non minion enemies.
There are two possible solutions to this. I don't know if the game uses either. First, you could reduce the amount of XP a minion is worth relative to a normal monster of the same level so that more minions are used per encounter. So when 75% die, there's still a good handful left. Second, you could increase minion defenses so that they don't get hit quite as easily as regular monsters of their level.
Overall Architecture
I think the overall architecture of the game is incredibly strong. There's a lot of design space available, and a lot of flexibility.
In some places that architecture is so clear, though, that you can sort of see future releases before they happen. And that gives the game a bit of an incomplete feel. For example, it was pretty obvious that more superior weapons were coming. The bastard sword made it kind of obvious. I think the same is probably true of damage increasing feats for arcane and divine classes. The game is playable now, don't get me wrong- but I think that the power level for certain classes and builds is dragging due to lack of feat support, and that WOTC expects to fix this in future releases much like they fixed the bastard sword's supremacy with Adventurer's Vault.
I have mixed feelings on this.
On one hand, its annoying to feel like the game "isn't complete," and when these things get released people will run around shrieking "power creep! power creep!," and that will annoy me further.
On the other hand, the PHB is enormous and packed full of information. Short of deleting white space, flavor text, and turning it into a vast reference book, I don't know that more could have been included. And the game itself is a vast wealth of options and choices. So... I don't know what solution would have fixed this problem. Shrinking the game would have, but that wouldn't make me happier. So while its annoying that our Fighter had to wait for Adventurer's Vault to find out what a superior version of the Maul looks like, and its doubly annoying that the feat starved arcane and divine classes are going to have to wait even longer for aid and comfort, I'm glad that the game as a whole has as much stuff in it as it does. Even if it has to go in multiple books.
Chromatic Dragons
They still exist. I still hate them. See other previous rants for details.
Versatile Weapons
Alright, seriously. Versatile is a worthless trait. When you create your character, you decide whether he's going to use a one handed weapon, or a two handed weapon. If you choose two handed, you go for a real two handed weapon right away. If you use one handed, you might use a versatile weapon, but you'll be holding a shield so you'll never use the versatile aspect of your longsword. It might as well be a one handed weapon.
The only thing that versatile does annoy halflings.
This doesn't have to be true. There exists the potential for an extremely good versatile weapon using fighter build. I hope it is someday written. All you really need to make it work is some kind of benefit for fighting with a weapon and an empty hand, and a special damage bonus when using a versatile weapon two handed. Then you'd have meaningful choices between attacking with a versatile weapon wielded two handed, and switching to a weapon/open hand combination.
Roles aren't Destiny.
They're not. Every class travels outside of their own role at least a bit. Some a lot more than others.
Power Source is Destiny
It is. I expected that at least the Paladin would mix martial attacks with divine powers. It didn't. I have mixed feelings here again. I feel like there's some design space available that isn't being used.
I think that's it.
Below are miscellaneous thoughts, criticisms, and predictions about areas of 4e. They are in almost no particular order.
Character classes I've seen in use:
Fighter, Maul
In spite of early concerns that this character wouldn't be durable enough to perform as a defender, he's done just fine. The high damage of his weapon helps make his class abilities more effective, and he's chosen powers that help him regain hp. The complete lack of any armor check penalty has been a quiet MVP for this character, since he can climb and jump better than anyone in the group. This enhances his mobility in unexpected ways, and gives his player a thrill.
He chews up a lot of healing surges, but he has 11.
Cleric, Laser
Temporary hit points on tap seems to be the best option here. I think this player would drop Lance of Faith in an instant if there were more at wills available, since its damage isn't that much different from Radiant Surge. Daily powers are incredible. Not a lot to say overall, though- about what I expected from a cleric.
Healing Lore could be reworded to clarify how it works with continual healing and with healing from paragon path abilities or cleric only feats. Its text is unambiguous, but seems not to match the intent.
Rogue, Brutal, Rapier (rethemed as katana for extra fun)
Its odd, but this character's encounter and daily powers are rarely used. I think they're going to get switched out soon. See, so much of their damage comes from sneak attack that switching to a more damaging power just isn't that useful- and if you have to attack AC instead of Reflex, it may even be counterproductive. So I think the way to go here is to use encounter and daily powers for effects, not for damage.
This class is frontloaded, big time, especially with a human brutal rogue, Backstabber feat, Nimble Blade, and Piercing Strike. Xavier's attack against a flanked foe was +10 v ref, 3d8+6 damage, at level 1. I don't think it breaks the game, but I think you can definitely see a change from overpowered to balanced as the game progresses from level 1 towards level 10.
He doesn't do well without allies to help him flank. I am reminded of multiple times that single goblins, below his level, have beaten him down. Its become a running joke.
Ranger, Two Bastard Swords
This character gets herself into trouble a lot. She's highly mobile, and can move amongst her foes easily, so she uses that ability to flank with the Fighter. And then she gets flanked too, and takes a lot of damage. She probably takes more damage than any other character in the party. But she's still alive, so I guess that's ok.
Twin Strike, coupled with Hunter's Quarry, creates an oddly consistent damage output for a Striker. Her peak damage doesn't tend to be as high as that of the rogue, and sometimes I think she wishes it were higher, but I'm pretty sure that if we added up total damage per combat she'd be tied or ahead. She also occasionally feels bad because her daily powers promise her so much damage, but they also require multiple attack rolls, at least one of which always misses, basically guaranteeing that she never actually gets as much of the promised damage as she was led to expect.
I probably should funnel her better weapons. I think she's behind, due to the difficulty of getting two identical bastard swords into the game while using modules. I'll look into that.
Wizard, Orb, Fire Magic
Some people complain about the wizard, but I've never noticed a problem in our group. Our wizard's damage output is quite adequate. Fireball and Shroud of Fire account for an awful lot of pain per encounter. Fireball is responsible for our Highest Damage Attack Ever- almost 60 damage with a single attack at level 5. And it could have easily gone a lot higher- there were only four targets in the blast at the time, and the damage rolled wasn't particularly high.
The fact that Cloud of Daggers auto-kills minions seems like a glitch to me.
Warlock, Fey Pact
I think this class gets a slow start. Also, its really hard to use to full effect. Basically, you have to arrange things so that enemies die at choice moments and power you to complete your master plans. This rocks when it works, but has the potential to go very wrong.
Also, some of the early powers seem underpowered. I mean, Charisma v AC? Seriously?
Looking ahead, I don't think this will be a problem long term. But at least for the fey pact, the damage is low. The action denial is crazy good, mind you, particularly once you hit paragon tier. Like, seriously, crazy good. This is probably one of the best characters to have around when facing a solo or an elite. Not... not really a striker though? A different pact seems like it would be more striker-ish, given that the other two pact at wills can potentially deal almost twice as much damage. And they still have a bit of control in them, for that matter.
Teleporting infinitely is cool, but eventually less useful than you might want. You know, after the second or third time you've teleported in a single round. The feat that grants a second pact should be a help here, so she can alternate between teleporting and gaining temporary hit points.
Nothing on the warlord or paladin, sorry. Haven't seen them in use.
General comments on other matters.
Items
I would have preferred even fewer item slots, but whatever. Everyone else in the world but me loves their l3wt. I can't complain much if incredibly popular aspects of the game haven't been fit to my personal preferences.
Multiclassing
I love the multiclassing system, sort of. I love the idea of dipping by means of a feat into the abilities of other classes. I disagree strenuously with those who feel this isn't "true" multiclassing. Its true enough for me. If I can play a smart guy in heavy armor with a sword who can also toss a fireball or two, I feel pretty darn multiclassed.
The problems I have are thus- to multiclass well, you need the following: 1. A strong stat of the appropriate type that you can increase as you level. 2. Usually a strong weapon or implement of the relevant type. 3. A third arm to hold that implement. The last one presents the greatest difficulty. This is a patchable problem, but it is an issue.
Strategy
I suck at predicting low defenses now. I haven't figured out if this is the system or just me, dealing with a new paradigm. When I DM, I make sure to give my players feedback on this subject, and to describe monsters in a way that will suggest to them the best approach.
Minions
Mixed opinions here. I love the idea of minions. But the specific minion rules they've used, coupled with certain powers, give me a sense of disconnect. Cloud of Daggers auto kills minions by leaving them stuck in a zone that does about two damage when used by our wizard. But Reaping Strike, which automatically does at least 4 damage when used by our fighter, doesn't auto kill a minion. Slashing Wake auto kills minions, but Fireball doesn't. I'd like some consistency, and beyond that, I'm not sure that a minion should ever be automatically killed at all.
Plus, minions devalue at higher levels. I don't know enough about higher level play to know whether this is factored in. It could be, honestly, it would be pretty easy to do. But I haven't checked.
The reason minions devalue is because area of effect attacks are more common and more precise. At level 11 our party will have a cleric who can drop a per encounter close burst 8 that damages only enemies, and our wizard will be able to do multiple similar attacks. That basically means that the first round of combat will kill about 75% of the minions present, while still dealing acceptable damage to the non minion enemies.
There are two possible solutions to this. I don't know if the game uses either. First, you could reduce the amount of XP a minion is worth relative to a normal monster of the same level so that more minions are used per encounter. So when 75% die, there's still a good handful left. Second, you could increase minion defenses so that they don't get hit quite as easily as regular monsters of their level.
Overall Architecture
I think the overall architecture of the game is incredibly strong. There's a lot of design space available, and a lot of flexibility.
In some places that architecture is so clear, though, that you can sort of see future releases before they happen. And that gives the game a bit of an incomplete feel. For example, it was pretty obvious that more superior weapons were coming. The bastard sword made it kind of obvious. I think the same is probably true of damage increasing feats for arcane and divine classes. The game is playable now, don't get me wrong- but I think that the power level for certain classes and builds is dragging due to lack of feat support, and that WOTC expects to fix this in future releases much like they fixed the bastard sword's supremacy with Adventurer's Vault.
I have mixed feelings on this.
On one hand, its annoying to feel like the game "isn't complete," and when these things get released people will run around shrieking "power creep! power creep!," and that will annoy me further.
On the other hand, the PHB is enormous and packed full of information. Short of deleting white space, flavor text, and turning it into a vast reference book, I don't know that more could have been included. And the game itself is a vast wealth of options and choices. So... I don't know what solution would have fixed this problem. Shrinking the game would have, but that wouldn't make me happier. So while its annoying that our Fighter had to wait for Adventurer's Vault to find out what a superior version of the Maul looks like, and its doubly annoying that the feat starved arcane and divine classes are going to have to wait even longer for aid and comfort, I'm glad that the game as a whole has as much stuff in it as it does. Even if it has to go in multiple books.
Chromatic Dragons
They still exist. I still hate them. See other previous rants for details.
Versatile Weapons
Alright, seriously. Versatile is a worthless trait. When you create your character, you decide whether he's going to use a one handed weapon, or a two handed weapon. If you choose two handed, you go for a real two handed weapon right away. If you use one handed, you might use a versatile weapon, but you'll be holding a shield so you'll never use the versatile aspect of your longsword. It might as well be a one handed weapon.
The only thing that versatile does annoy halflings.
This doesn't have to be true. There exists the potential for an extremely good versatile weapon using fighter build. I hope it is someday written. All you really need to make it work is some kind of benefit for fighting with a weapon and an empty hand, and a special damage bonus when using a versatile weapon two handed. Then you'd have meaningful choices between attacking with a versatile weapon wielded two handed, and switching to a weapon/open hand combination.
Roles aren't Destiny.
They're not. Every class travels outside of their own role at least a bit. Some a lot more than others.
Power Source is Destiny
It is. I expected that at least the Paladin would mix martial attacks with divine powers. It didn't. I have mixed feelings here again. I feel like there's some design space available that isn't being used.
I think that's it.
