1. Setable via Siri
2. Dimmable
3. Select Song
4. Gradually raise volume of alarm sound
5. Can run in the background
6. Overides Vibration Mode
7. Snoozable
To me these are basic functionality coming from Android but IOS seems to be lacking.
I've bitten the bullet and purchased Sleep Cycle alarm clock by Northcube AB https://appsto.re/au/jabht.i it was highly rated on the App Store. Not sure if I'll use the easy wake function or the sleep data but it can just work as an alarm clock with adjustable volume that works with all your iTunes music as well. Only draw back is it needs to be charging all night as well as being set which isn't an issue for me!