To the best of my knowledge, you're the only one holding that opinion.
Well, UngeheuerLich gave me XP for it, so maybe not the only one.
I've played defenders. You can make it very hard for anyone to escape you. You just have to play smart and pick powers to make you sticky.
Yeah, been there, done that as both a DM and a player. There are scenarios where Defenders are stickier, but it's usually closer to sticky notes than concrete.
I'm a Swordmage player (it's my friend who prefers Fighters, though fwiw I'd say he's better at defending than I am). Just for example (since one of your complaints was that CAGI is 7th level), here are the 1st level powers I prefer:
Aegis of Shielding
Booming Blade
Luring Strike
Foesnare
Dance of the Sword
Aegis of Shielding does nothing to stop an NPC from attacking someone else. It lowers the damage and gives a -2 to hit. And, it's usually one foe. Sorry, but that is not stickiness. That's debuffing and even the -2 doesn't do much compared to a lower AC PC that can be attacked.
Booming Blade does nothing if it misses. It does extra damage if it hits. At higher levels, that damage is relatively minor (4 to maybe 8 damage) when compared to what can be done by the monsters to other PCs. And, it's one foe. This is not even in the sticky category.
Luring Strike does nothing for stickiness unless you hit and unless you move the foe up against a wall or maybe against difficult terrain. So, maybe a 50% chance to be close enough to a wall in a smaller room and a 60% chance to hit your foe. So maybe one round in three against one foe in a small room or one round in ten against a foe in a larger room, this stickier solution might work. Might. This doesn't sound very sticky if it rarely works and is only against one foe.
The At Will powers you listed here do very little for stickiness. It's illusory.
Foesnare is the only one of the bunch that is reasonably sticky. Even it won't necessarily stop something like a Close Blast (or a Ranged attack, but that provokes), but it does reasonably well for melee attacks.
Dance of the Sword is semi-ok with regard to stickiness for any foes standing next to the Swordmage, but it too doesn't actually stop the foe from moving, just OAs and shifting. So NPCs further away in the burst aren't necessarily hindered in any way.
Except for Foesnare, none of these attacks actually stop a foe from moving away from the Swordmage and attacking someone else. Soft stickiness, not hard stickiness. Some of them will result in an OA if the Swordmage uses them, again, assuming that a different NPC doesn't move the Swordmage first. The game is not played in a bubble. Most of this is not forcing in any way. The DM can have the NPCs do whatever he wants for the most part. That's the part of this equation that you appear to be missing. Defenders penalize foes for attacking someone else, they typically do not prevent it.
Every character type has a weakness in 4e. Fighters tend to be poor against either Reflex or Willpower. So on and so forth. So what if the wizard has a weakness too? Is it that some people are too used to layering on spell after spell until they had no weaknesses left? 4e doesn't let anyone do that. The wizard isn't being singled out.
One has to look at the odds of each of these being used. Let's assume AC is attacked half of the time and the other 3 are each attacked 1 time in 6.
Yes, Fighters can be poor against Reflex or Will. But, they have AC (50% of most attacks) and Fort (16%) locked up. Typically, they have either Reflex or Will covered, so they only have a defense weakness against about 16% of all attacks.
Wizards typically have 2 of the 4 covered (Reflex and something else) and the often used AC isn't usually one of them (shy of feat/power tax). So instead of being low defense for 16% of attacks, he's low defense on 66% of attacks. Plus he has fewer hit points. Lose lose. His non-Daily powers (the vast majority of his attacks) really don't make up for this because they are not that much more potent than attacks from other PCs.
Seriously, have you actually played a Wizard against a DM who doesn't hold the player's hands and has intelligent foes go for the jugular, and a DM who creates unique unexpected or rarely seen challenges?
Look man, I'm not going to dig through all those posts to figure out the specifics, but from what I could gather this is an atypical fight if I ever saw one. This sort of thing is exactly why I specified a typical fight. It's not that there's anything wrong with the challenge that an atypical fight provides, except that those types of fights don't often accurately correspond to their supposed difficulty level.
Like I said, in my games, having unusual terrain features is pretty typical. In this case, the size of the room was part of the XP handed out, the foes themselves were pretty wimpy but used terrain INTELLIGENTLY (the thing we have been talking about the entire time, intelligent foes). This particular map came from one of the WotC modules. So if you consider small 6x6 rooms where the Swordmage can sometimes push a foe up against the wall as typical and the monsters in the next room over don't come and investigate when a fight is going on, whatever. To me, there is no such thing as typical or atypical. PCs have to be able to adapt to all situations.
You cannot have it both ways. If the PCs are in a large room, the Defender will require time to get to each foe and the foes can spread out. Sure, the Wizard can be at the far side of the room, but the attackers can mostly ignore the Defender and use ranged or melee attacks against whomever they want.
If the PCs are in a small room, then the Wizard doesn't have room to get away. Sure, the Defender might be able to more easily partially lock down one or two foes, but the squishier PCs have nowhere to go to avoid bursts and blasts and if foes get in their faces, they'll have a harder time running away. If they run out of the room the way they came in, nothing usually stops a monster or two from chasing after them.
I also note your comment on Wizards just running away a bit as a viable Wizard solution to attacks. That can make it tough for the Leader to come heal the Wizard if the Wizard is far away when he gets knocked unconscious. These types of generic tactics like running away usually don't work well for one reason or another in many encounters against intelligent foes. For example, Wizard runs out of a room, monster closes door to the room, the Wizard is cut off from the fight. Seriously, do you consider running away a GOOD defensive tactic for the party as a whole?
One other note. Most monsters have really good initiative modifiers (a Wizard, not so much, even with Improved Initiative unless he is a Dex Wizard which makes his other defenses weaker). Unless the PCs have ways to boost their initiatives, on average, monsters tend to often go early. Intelligent monsters should use this to put PCs at a tactical disadvantage, right from the start.