Being able to change the orientation of the wingmirror would be really nice. Would be an easy way to see what is in your blind spot without having to change your own view.
I'm guessing the rear-view mirror and the wing mirrors are most likely the same render, for performance. You'd obviously need to have sperate renders for the different orientations. Although I don't imagin an -optional- additional render for the wing mirrors would be a too much of a performance drain.
Just think its a very simple way to see what is in your blind spot. I really don't like using the change view keys while in a pack of 10... turning... and trying to see where everyone is by changing view. Its just disorientating.
Anyway, just a simple idea.