I read somewhere that Apple is denying low-level hardware access to Adobe, and that's why then can push performance to match than on the Windows platform. The thing is, Is it right for a browser plugin to have such access "to the metal", for security reasons and others pertaining software design. Adobe, in turn, is not releasing the source for the flash plugin for Apple to modify either.
My opinion is that, again (read: Creative Suite), Adobe just wants to get away with a lazy port of their windows codebase to the Mac, and not play by the rules (read: Cocoa, Core Animation, etc.), but again, I don't have all the facts. It is not a 100% informed opinion, but whose is?
I am not that flash-dependant, I don't watch too many videos on the net (mainly text pages on my iPhone). It is very exciting that Apple has the balls to push for a move which is painful and unpopular at first, but in the long run will be beneficial (wide spread of non-proprietary web standards, accessible media, cpu/memory efficiency, etc.). Right now Adobe has kind of a web video monopoly and all mac users know it doesn't help them improve.