I'm not sure if somebody has already suggested this idea, but because there's already some statistical information about listened songs, it wouldn't
be too hard to implement at least the following two features:
1) ability to detect songs which users don't like (songs skipped before the end). kPlaylist already saves this completion status in percents in the database. For example, there might be some kind of rating system, where completing a song would increase its points by 3, and skipping the file would decrease its points by 1. "Hot files" have many points, and "these suck" have -50 points... Randomizer could take these points in the account too.
2) Admin interface: ability to delete/move these bad songs away, or get a list of them, so an adminstrator can make something about it.
It's really hard to detect and cleanup these old songs which nobody want's to listen anymore (or worse, have never wanted). Skipping the song is easy (remotes for winamp), but if you must come to write every song name down, it sucks.