Well, iOS is fundamentally designed as a platform to launch apps from.
The software innovation is meant to lie within the various apps. Google have gone further than this with Android and sort of tied the OS into the apps more so than Apple via widgets and the greater degree of phone control that Android apps can have.
I like iOS for the simple nature of it, and the unified feel, but Google aren't far away from that with Jelly Bean on the Galaxy Nexus, it really is excellent.
As for what Apple could do, I'm not sure really... I think they'll be okay for the moment with keeping the innovation within the apps themselves. Perhaps some new icons though, the current ones are 'iconic', I guess, but a change wouldn't be a bad idea. Perhaps some live icons like the live tiles on WP8; so that the weather could change on the icon itself, for example. Hardly amazing innovation but a few small things like that would go a long way.