Make your Screen Options and Help tabs more noticeable.
I work with a lot of people who are new to WordPress, and they are just never aware of the Screen Options tab. It's one of those things that you need only rarely, that power WP users are well aware of, and that is a complete mystery to noobs.
No, other than to let users choose which color scheme they would like. Just because you're working on the backend doesn't mean you shouldn't have a nice view.