this is what i can found in my ipad mini retina after update to iOS8.
- Camera new features - Time-Lapse , Timer (Front & Rear Camera)
- Photo App - No more Camera Roll has been changed to Recently add, but cool thing is u able to categorize your photo to Favorite, and after deleted in recently apps it will moved to '' Deleted album''.
- Of cause, new wallpaper in Setting apps.
- Now you can add widget in Notification center and customize it.
- Appstore redesigned.
- Support 3rd party keyboard (You can download in Appstore)
- New interface on Control center. (Uglyyyy)
- Able to check Battery usage in setting.
- iCloud Drive added.
- Double tap it will have recents contact icon above.
- Tips apps - Get familiar with iOS8 (Cannot be delete)
- iMessage - Record voice and video directly in Apps.
- Mail apps with more shortcut key.
- Handoff (Not available yet)
- Family Sharing feature