The web went crazy yesterday over the possibility of Apple being able to remove apps from your iPhone through a blacklist folder in iTunes. Even though this turned out not to be the case I'm struggling to see what the problem might be.
If Apple were to decide to revoke an app it would surely be as a result of a security breach or risk. I for one would be happy for Apple to automatically delete an app that was going to compromise my iPhone's integrity. In fact, I'd want them to do it over the air rather wait for me to sync back to iTunes.
Otherwise I can't really see any benefit for Apple being able to revoke apps - it's not like they'd kill an app because they had fallen out with the developer or anything trivial like that.