On #7 skills - I have not found a problem yet; Hard DCs go up by around 23 points over 30 levels, 19>42; PCs with training & focus in that area tend to increase skills by around 3/4 of their level, same as monsters (monsters' ability scores go up by 1/2 their level giveing a 1/4 level boost to checks, plus the standard 1/2 level bonus). So a 30th level PC focused in an area is about +22 or +23 over his 1st level self. DCs that untrained/unfocused PCs are expected to beat need to be much lower of course.
Do you have to scale DCs for how competent your party is?
A character unskilled and unfocused at something gets +16 over 30 levels, with a baseline of +0 or so.
A character skilled and focused at something gets +27-32 over 30 levels (15 level, 4-5 stat, 6 item, 2-6 feat), with a baseline of +10 or so.
Already at level 1, characters with high and low skill checks are auto-succeeding or auto-failing where the other character is challenged. By level 30, this must be assumed -- anyone with any chance at a high skill check will auto-succeed on easy, and anyone with any chance of failure on easy will auto-fail on hard.
So opposed skill rolls vs monsters, or rolls vs Passive scores, should work at all levels (unlike in 3e).
Mostly, unless someone works at it. So if it matters (if you can win an encounter with a skill check), skill op will be really strong. But in practice, skill op is rarely strong, so few people do it.
But I agree there will clearly be a problem at high level with skill rolls vs monster defences, since the numbers (bonus vs DC) diverge by around 8 points.
It is worse than this -- bonus vs DC diverges in both directions at once! Heavy charop can result in skill bonuses that dwarf defences, and lack of heavy charop tends to have things go the other way.
It is a flaw.
On #10, I have used Inherent Bonuses for the past 2 years and they completely solve the Crippled Without Items problem; a powerful weapon might give +1 to hit/damage over a mundane one, plus some nice crit bonus dice. For three-Tier play I think Inherent bonuses are vital. I am experimenting with not using them in an upcoming three-level mini-campaign, so that +1 items feel significant, but I would never not use them in extended play.
Ya, but that is more than a bit of a hack. If you where reworking 4e, that kind of clunky mechanic should be avoided.
Re chickenscratch from high [W] attacks - I find the game runs much better with all monster hit points halved; at worst the occasional standard monster drops a bit quickly, but elites and solos feel just right now. I also give minions a Damage Threshold, making very low-damage attacks less effective. Multi-attack still generally beats high-W attack, I have not seen a problem yet (levels 1-10, 2011-12) but I expect it will be an issue by Epic tier ca 2015.
I am guessing your players are low-op, because by paragon a daggermaster rogue MC avenger critfisher can pour damage out that just isn't funny (let alone the half-elf twin strike variant).
Half HP means that low-op players experience a game pace more similar to high-op, but high-op with half HP would be pretty silly.
The problem with high-[W] attacks isn't just that they do little damage, it is that they are in exchange for other stuff. And the extra [W] is really crappy.
So it becomes optimal to pick lower damage, higher status effects (like stun), or multi-tap powers, all of which lower the damage per second of your group even if they increase character effectiveness. An extra 10-15 damage at paragon in exchange for a one round stun is a bad deal.
