Head-bobbing or taking control of the camera is ultimately bad in VR and can cause major sickness.
I've noticed something however and that is that if I turn with the mouse in VR (fps demos) where vertical movement is not locked and speed overall is more variable than a gamepad I seem to get less prone to sickness. When you turn with most gamepad demos the vertical movement is locked and the overall rotation-speed curve is usually very flat (despite sticks being analog).
Have anyone experimented with vague head-bobbing or variable speeds (as if you are taking pivoting steps) when turning in a FPS demo?