Right now, all you can do is enable/disable displays and set their resolution/rotation. You have to pray that it sets a display up properly (does the user want a second screen mirrored? to the right, or the left? something else?)

This really needs improvements. A good reference would be the tool arandr, which allows a lot of freedom, yet stays very lightweight:
http://christian.amsuess.com/tools/arandr/