Yay! I'm not up to date on what improvements have been planned, so I just thought I'd put this here and hope someone read it :P As you have! :)

Another site that has a very nice list of genres, that the members have all contributed to is http://www.lemonfingers.com/v1/bookshelf.php
You should take a peek at how the genres are organised there if you're interested in redoing ours, to take a peek and see what works elsewhere :)