Perhaps the biggest omission in the whole system remains active notifications, which Apple just introduced for the Mac in OS X Mavericks but hasn’t thus far announced for iOS. The ability to quickly respond to a message, reset a timer, or otherwise handle simple items without having to switch apps is even more necessary on mobile than on the desktop. Hopefully actionable notifications on OS X are just a precursor to the same or similar system on iOS, and sooner rather than later.
I hope this comes really soon, like final release of iOS 7 soon. It doesn’t make sense to show it off in OS X and not in iOS unless it was not ready, which I’m hoping is the case.
Another minor annoyance is also addressed by Rene and I hope Apple does so as well:
Unfortunately, for all iOS 7’s objectification and direct manipulation the demos to date haven’t shown any gesture-based way to dismiss notifications. Other platforms have allowed you to swipe away notifications for a long time already. Even Apple’s own Mail has a swipe-to-delete feature, and the immediacy of “tossing things away” is tough to beat. Hopefully Apple addresses this, because the tiny little X button is discoverable, but not very usable by itself.