Some periods you focus more in some artists, other periods you focus more in other ones. It didn't happen to you that for some weeks you're listening to the same artists (or groups) again and again?
How about a kind of 'Quick Artists Playlist'?
Basically, a playlist that could work that way: in the Music Library you'd have the option 'Add this artist to que Quick Artist Playlist'. And of course, in the playlist, you'd have the option 'Un-add this artist'.
Right now you can do that with Smart Playlists. That simply would be a quick way to add (and un-add) artists to it.