I think you can use older trackIR cameras with freetrack and have full 6 DoF as a temporary solution
I actually like the feature, it's like having to tighten the straps to get a steady sight picture (it also reduces head-shake during high-G maneuvers) at the cost of not being able to turn around in your seat that much.
That being said, it needs some fine tuning but i wouldn't want a complete return to how things were in IL2:1946.
My idea for a solution:
1) Let the player save his default view position, like it happens in RoF: move around the cockpit, press a key combination and now your center defaults to that position.
2) Use the above method for centering the gunsight and make the straps command independent of gunsight view. They would just be about reducing how much headshake we get in violent maneuvers while maintaining their viewing angle limitations that they have now.
3) Use 1 and 2 when in the pilot's seat, but don't change it and use the current system for when we are in the gunner's seat (you can press the same command and you get a view down the sights of the gun, much easier to aim this way).