I think iOS 7 is a huge improvement. But I don't like the cover art when scrolling the artist and songs pages or the fact that when you go to an artist it shows all their albums as well as songs on that page forcing you to scroll a lot to find the right song. Some gestures in the app would be a nice step also. The calendar is a mess as well but I've long since moved onto superior third party agenda apps.
This and some other issues with how iOS 7 handles music and podcasts are the only reason I haven't upgraded my devices yet. I like the new features and could adjust to the new design, but for me these are primarily devices for consuming audio.