Straight to the point: I want to reorder playlists in the Android app. When trying to build a new playlist from assorted songs, I am unable to change the position of song X if I decide that it should go before song Y without wiping out everything after song X. Adding a drag-and-drop kind of editing to the "Now Playing" playlist would make this so much easier. Being able to reorder existing playlists before queuing them would be helpful as well, as I sometimes combine several existing playlists to create the new one.
With the addition of remote control to the Android app, Subsonic has fast become the only audio player I use inside the home (it has long since been my player of choice on the go). Add this feature and I can stop fussing with other playlist creation tools. Then we can move on to other things, like uninterrupted playback when transitioning between devices...