Did anyone find a solution yet?
I have the same issue as the OP (mouselook only lets me turn about 90 degrees to the left or right). However I found out something: this effect is caused by the mouse cursor (the INVISIBLE mouse cursor) hitting the border of the screen. I know this because if I then disable mouse-look and get the curser back on screen it appears right there on the border of the screen even though I had it in the middle when I made it disappear by toggling to mouse-look. So if I now (with the cursor back on the screen) move the cursor back to the center, then re-enable mouse-look I can turn another 90 degrees (until the invisible cursor hits the border of the screen again.) I can repeat this as often as I like and turn as far as I like. But only in these 90 degrees increments, because I always have to get the cursor back onto the screen, return it to center, then go back to mouselook, turn further etc.
So the issue is that the game traces the invisible mouse cursor even when in mouse-look and stops the turning when the invisible cursor hits the screen border, blocking its movement.
Another thing I found out is that (for me at least) this happens when I play on another computer via remote-desktop. I do not have this problem when I play on my own comp with the mouse directly connected to it. But when I use remote-desktop (with the mouse of course being connected to the client while the game runs on the host i.e. the mouse is not connected to the computer that the game runs on) then the issue appears. I find that interesting.
I wish I had a solution though :P
