Not necessarily in order of preference.
- Picture lock, ala Windows 8. Not face recognition, the photo password thing.
- Ability for apps to plug into Spotlight. Ex. Search my Evernote from Spotlight.
- More app integration points like "Open With". Allow any app to register itself as a "photo provider" (fb, flickr) or "share provider" (twitter, fb). Instead of importing photos from the camera roll, allow import from any photo provider, of which the camera roll is just one of many. Android has this as well as Windows Phone 7 and Windows 8.
The photos example is one of the best, but also imagine a more generic "document provider". I'm in a text editing app like Byword and choose to "open document", I see a list of apps that provide documents. In that list is Dropbox. I open the file. Document providers are 2-way, so as I make changes to my document in Byword it is saving back to Dropbox. Byword doesn't have to do anything special to implement this. The Dropbox app, as provider, handles all