Here is a quick run down of a few new features I've been able to find.
1) iMessage - it finally has the tools to match the Facebooks, WhatsApps and Snapchats of the world. There is third party app intergration, an entire keyboard app store, you can send stickers, GIFs, handwritten messages, animated emojis, photos with doodles and light show effects.
2) Photos - now trying to compete with Google Photos (which I use) it has an AI integrated to index your photos and search by objects in the photo and facial recognition abilities.
3) Music - they cleaned up the look of the app finally to be more appealing like Spotify (i am not sure if I will ever leave spotify for apple music though)
4) Siri is now integrated with third party apps to call us ubers and what not
5) Lock Screen and Widgets - this is the biggest change. The widgets are sick and actually usable and the lock screen has more shortcuts and a new way to interact with the device.
6) YOU CAN REMOVE STOCK WIDGETS NOW
7) Visual link-sharing in messages
8) Song lyrics are embedded in apple music
9) Voicemail transcription is available
10) Apple pay on mobile web
11) Third party extensions in Maps
12) Optimize music storage for Apple Music Subscribers
13) New Bedtime feature in Clock app which is rly cool
14) launching your camera will no longer stop your music
15) Can control the flashlight intensity in control center
and much more I haven't explored yet.