It would be cool if there was a program that built a database out of your raw audio files, and that database was read by media servers like mpd. I want the user contributed data, but I don't necessarily want it to replace the original files.
If I lost my whole music collection tomorrow, I could recover the actual tracks from Bandcamp/7Digital/rip etc. But my custom tags and ratings that I use to generate playlists, and the history of saved playlists found back over 15 years, would be impossible to recover.