I don't think I see how merely separating the App Store from the hardware division provides that benefit, unless you're meaning something different than the way I'm reading it (that is, just making the App Store the responsibility of a separate App Store Company but changing nothing else).

Allowing iOS to sideload apps would be a more direct cure for this, because Apple's decisions about what belongs in the App Store wouldn't necessarily translate to decisions about what belongs on the platform. That would solve a fair number of problems for other developers, actually -- and in the long run would probably benefit Apple, too, by virtue of improving the overall health of the iPhone/iPad platform.