Just that, say you play one of the survival horror games that people are waiting for to hit VR, you get jump scared and have to run away from the monster and you just blow straigh into a wall. unless of course it starts to show the turning thing way before you a wall (like 2 meters away) which would mean you have to have big room to play in.
For the other idea, the game could pause during rotations. Would be annoying, but it wouldn't destroy the game mechanics.
No solution is going to be perfect. I think people interested in this will probably have to do it outdoors, or at some public space.