While I see your point Joe, I think a lot of those other games are repetitive. I read through the new DC game and while their version of classes looks intriguing, it's unnecessarily clunky in the chargen dept. But 4E is pretty brisk and a really robust system. It's already got powers, and healing surges are more believable in that kind of setting anyway.
WotC is coming out with Gamma World next month--I think that's proof enough that the rules are ready to support mutations, powers, etc. with some real gusto to boot!
I've also read a few blogs that are toying with the idea of using 4E along those lines.
I say do it!