Nice to see a balanced view from a doubter. I can't stand the '4E is crap no matter what' people. I don't mind them existing, I just can't understand why they come on forums about 4E just to dampen everyone else when they have no interest anyway. I found your comments very interesting.
The skill challenge thing is my biggest worry. I think it is very interesting and the right way to go, but from what I have heard I think it sounds like it hasn't matured enough.
Have to say, though, one comment that has pushed my frustration button is your comment on hit points becoming less health points. I keep seeing this worry being thrown about. The reason I get my frustration grumpy head on is this: Health has only ever been a small part of hit points. Hit points have always been a massive abstraction - luck, skill, will to keep going, divine favour, arcane infusion, etc. At least since the red box basic set to my knowledge.
It is the only way hit points have ever made sense.