iOS X wishlist so far:
1. Improved DND, e.g. ability to schedule multiple DND periods per day and/or create weekly pattern, contact exclusions affect not just calls but also messages and other 3rd party apps (see 2)
2. A contacts API which enables 3rd party apps to notify the OS that a particular contact was the original sender of a 3rd party notification. Currently, you receive a WhatsApp from John and iOS has no idea your contact John has contacted you. This API would allow that. Benefits: a) you can exclude a contact from DND (see 1) and their calls, messages AND any notifications from third party apps from them will be allowed through. b) your recent/frequent contacts in Siri Suggestions can be updated when contacts messages you through 3rd party apps. c) potentially other innovate things!
3. Even smarter reminder events like
a) when i wake up - could be based on a multitude of things, alarms, movement of the iphone in the morning.
b) when i call x/when x calls me - stealing from windows phone. (along with contacts API in point 2 above this could also work with when you call contacts in 3rd party apps like whatsapp, skype etc.).
c) when i use x app etc. etc. etc.
4. Multiple accounts. The rumours from 9to5mac just before ios 9 about ios 9 were spot on, and included a thing about multiple account not being done in time but will hopefully feature later or in iOS 10. So fingers cross they come through on this. Hope it's on at least some of the Air & Mini series and not just iPad Pro.
5. Rotation lock idea someone mentioned recently - add an option to allow landscape mode even when portrait locked if a video or photo is on screen.
6. Notification after a screenshot is taken, allowing you to go directly to the photo in Photos (pull down actions might include edit, share, etc.)
7. WiFi management - list known wifi networks, allowing you to prioritise them, view passwords, forget them without being in range, etc.
8. Bluetooth management - allow you to rename/alias devices like you can on mac os - so devices with the same factory name can be distinguished
9. More alarm clock options like volume, fade in.
10. Alarm clock API which lets third party apps set local notifications that can override DND and play custom alerts for longer than 30 seconds and have the same fade options etc. A lot of apps do various things to try to get around this but Apple could help. Would require strict enforcement by Apple so that apps don't use it illegitimately.