iOS 7 [has] removed the ability to view individual audiobook chapters in the music app. It has also replaced the chapter length with the length of the entire book in the time scrubber.

Both these features worked properly in iOS 6.

We have invested a lot in audiobooks on the iPhone and the removal/alteration of these features has diminished the value of our investment as well as the value of the phone. Put these features back in the next iOS release, specifically: