I have a feature suggestion which is a very simple change, but will make a huge difference to the speed and ease of navigating the app.
By far the quickest way to scroll through a list of hundreds or thousands of albums/songs is to use the "Fast Scroll" feature (by which I mean grabbing the scroll position marker on the right hand side which brings up the alphabetical popup, and manually moving the page to the position you want). The alternative of course is to repeatedly swipe to move the page down, which isn't very good if you're going to the bottom of a list of 3000 songs.
The problem with Fast Scroll currently is that it isn't very easy to activate. Fast Scroll cannot be directly activated as the scroll position marker is not normally visible, and only becomes visible when the user manually scrolls the page by swiping it. Then the scroll position marker is only visible for about one second. When near the bottom, it is even possible for the scroll position marker to be hidden behind the minimised Now Playing box. Even when it is visible, it is a very small target to tap and drag with the finger.
It would be far faster and easier if the Fast Scroll mode was automatically activated when swiping down from the top section of the screen. The user would be able to get to any position of a long list by a single swipe very quickly. It would be much better than having to swipe the list so that the scroll position marker appears for a second, then grabbing it and moving to the position you want. Please see the attached image for a clearer idea of what I mean.
This wouldn't obstruct any other features or require any design changes. Alternatively, a simpler change would be to make it so the scroll position marker is always visible and doesn't keep disappearing, so it can always be grabbed. There is no real benefit from it being invisible. (Preferably also make it slightly fatter so it is easier to hit, I have large fingers so it can be difficult to hit such a tiny target)