Kid Charlemagne
I am the Very Model of a Modern Moderator
How so, if you don't mind me asking.
PS has played a lot more 4E than I have, but I'll take a stab at it - if I wanted to house rule a class or create a new one in pre-4E I could do it in a page of text. Now I also need to invent or appropriate 30 levels worth of powers (how many pages does each class take up in the PHB?).
The 4E system is very flexible - except for the powers part. I really like almost all of it - except for the powers part.