I’m thinking it would be great to be able to assign arbitrary tags to my music, like I do to my photos. For instance, I might tag the finale to Beethoven’s Ninth Symphony like this:
symphony beethoven loud choir german
I can’t figure out how to Google for this sort of feature because, well, the word “tag” is already taken for something else in the context of music.
I believe Amarok offers it, a bit, but Amarok has too many other serious flaws for me to be able to consider it.