It would be nice to have an extended playlist management to save current playlist (queue) into a file (m3u) and to be able to load that file again with clearing current play queue (add, replace and play feature) or just append to current play queue (add). Just like the features from the database, which is very nice and brings a lot of comfort and high usability.
Another feature I don't know if this is feasible are smart playlists, songs added last 30 days, songs from the 80's and so on.