One thought might be to have the distance the knuckles are held from outside a certain sphere near body center reduce joystick sensitivity for the attitude axes. That way an arm could be held out for careful aiming, and brought in for maneuvering.

While it sounds nice, what if certain people are just more comfortable holding their arms out at different degrees? I think it should be an opt-in or require configuration for the hold-out threshold distance, but otherwise sounds like a neat idea.