I'm used to other rts games where right click is move, on unit it's attack, on special things it's doing whatever if the unit can do that..
Middle mouse button for me tends to not have a use, and not being able to pan the camera, in my opinion I think it's a great button, because to pan the camera you need the mouse anyways, might as well be a mouse key.
There is however the options menu to change that button to a keyboard key if you'd prefer, or switch it around a bit until your satisfied.
