The first implementation of controls was exactly as you proposed! But I did't like the result. It's just that rotation speed was not constant with the mouse movement. When you move your cursor to druid - you would spin like crazy=) In order to turn without any sudden rotation you needed to make a whole cemicircle above the druid, and with constantly increasing druid circle radius, it was harder to do.
So I decide to make it like this: you move your mouse left - you turn left, you move your mouse right - you turn right. This makes controlls much more predictable once you realized how they works =)