Now that I’ve analyzed all of the classes in the PHB2, on to answering the original question I was posed, of whether I think there is power creep in the PHB2. Accumulating the results of my previous examinations, I get:
Avenger > Barbarian > Melee Ranger
Bard > Warlord
Wizard > Invoker > Druid
Shaman > Cleric
Sorceror > Warlock
Warden > Paladin
So it looks like the answer is yes, I think the PHB2 classes are better than the corresponding PHB1 classes. However, I notice that most of the comparisons were to the PHB1 classes that seem weaker to me (no comparisons to the fighter or the archer ranger, for instance). And in general, the difference was not that large, and in many cases the PHB1 classes were less balanced and thus seemed better the more you looked at only the most effective powers and class builds.
There is a spectrum of character design going from picking options purely based on characterization, to pure minimaxing. I probably fall somewhere in the middle. With that style, I’d say that the PHB2 classes are, on average, a feat or two better than the PHB1 classes, so there is some power creep. But I feel like they are better balanced, which is nice.
If you are minimaxing – well, there are a lot of people analyzing the game who are more interested in that sort of thing than me. I wouldn’t be surprised to find that the most optimized PHB2 characters are not better than the most optimized PHB1 characters.