I tried renaming "%artist\%title%" to "..\%artist% - %title%". I didn't really expect directory renaming to be reversible in this way and it isn't, but you can use a literal in place of the ".." (I believe it is probably rejected due to a simple filtering problem.) Could we have an option to delete empty directories after a move or mass renaming?
Nearly two months have gone by and I gave this request little thought until I read two separate requests in alt.music.mp3 for a tagger with a feature that removes empty directories as part of the renaming process. I suppose it can be a real issue for some with large collections they want to reorganize.
I'll put this on my wishlist