My predictions for iOS 5:
- Spotlight screen gets a major overhaul and notifications added
- Dynamic home screens (depending on time zone and time)
- Enhanced folders (as stacks or lists viewable like Dock in Mac OS)
- selectable Folder icons
- Major overhaul of the Mail App (stars, flags, different fonts and styles)
- AirDrop for iOS & dedicated File App called Files
- iPhoto for iOS
- iWork for iOS
- New Multitasking API's (e.g. no complete sandboxed apps any more and enhanced communication between apps.
Like the possibility to add a task to Things or Omnifocus through the Mail app - like it is now in Mac OS)
- Voice integration in every app
- SMS app gets competitive with WhatsApp and other similar apps with BBM like functionalities.
- Webkit 2 for Mobile Safari
- Possibility on the iPad to view two apps simultaneously in landscape mode (except video playback apps)
That's all I can think of right now