iOS 10 doesn't need to be totally overhauled in terms of UI.
However... in terms of UI I would like:
- Dark mode, or at least a dark keyboard option. SDK for developers to integrate into their own apps. Would be functionality that could be used alongside or separately to Night Shift, either manually or on a schedule.
- Dynamic/subtle motion on icons like new Apple TV. More live icons like Calendar, for example Weather showing current temperature.
- New wallpapers, including new live and dynamic wallpapers
- Refreshed animations, taking cues from Apple Watch. For example, scrolling through Message histories, the bubbles would animate in more fluidly.
- Generally refreshed icons throughout entire system, moving away from bright garish colours to more pastel tones (slightly). A bit like what the "Darken Colours" option in Accessibility does to text through the system.
- Red dot at top of screen to signify unread notifications like Apple Watch - could be used instead of or alongside icon badges. Also tie notifications closer to badges - clearing notification center should clear all badges too.
- Move Today/widget view to live with Spotlight (swipe far-most right on home screen for Spotlight and Today widgets)
- Improve Notification Center to be more visual and useful. Clear all notifications dynamically if cleared on other devices.
- Less white through system - using transparency more in parts like in OS X.
In terms of functionality:
- Many stock apps (Music, Safari, etc) receive updates through App Store independent of OS updates
- Dynamic content in iMessages e.g. Links show previews of content, videos show thumbnails, etc. Large emojis when sent as individual messages (like Facebook Messenger).
- Improvements to iPad multitasking - 2 instances of same app side by side e.g. Safari
- New sounds (ring, text etc)
- Auto low power mode at 20%
- Voicemail for FaceTime
- Ability to type queries to Siri (alternative to using voice)
- Weather and Calculator apps for iPad
- Per-app rotation lock
- More control over Do Not Disturb scheduling
- Per-contact read receipts
- Fix AirDrop (temperamental at best at the moment)
- Ability to snooze Messages and Mails to reply to them later
- New photo filters in Camera app
- Ability to filter Live Photos
- Touch ID on Hidden Photos album and per-app in settings
Bug fixes, speed improvements and a slimmer profile a la Snow Leopard.
I hope iOS 10 is a substantial update both under the hood and in terms of user-facing changes. In addition to security and bug fixes which should be a given, it is definitely time for the UI to be really heavily polished, for the amount of bright white to be reduced, and for a Dark Mode.
I hope Apple really goes to town with this landmark update and gives us not only a refreshed UI, but improved stock app functionality. Mail for example could be better (apps like AirMail and to an extent Outlook are doing this better than Apple at the moment for example). Apple Music needs to be overhauled too, learning from the launch lessons.
High hopes.