I'm curious about the Music controls ... specifically the "Heart" location on the music app and on the lock screen music player? In my opinion, the iOS 9 Music was perfect, I really enjoyed the "Heart" being on the main playing screen and on the lock screen. When I run or I'm driving, it was so easy to "Heart" a track while on shuffle, or to easily see if it was already a "Hearted" track.
In iOS 10 Apple took the "Heart" status off the lock screen completely, and you can only see it in the Music app if you click the "..." in the lower right hand corner. So many extra steps. Any chance the "Hearts" have been moved back like in iOS 9?