I'd love to see a way to add the users role to the body tag of the theme. Obviously this would change depending on what page they are on, but it could reflect admin or authenticateduser when they aren't in a course, and then if they are a student or teacher, etc it would reflect that in the course pages.
I ask because it would be handy to be able to load custom css based on the role of the user. you could literally hide things from students with simple css tags.