How possible would it be to bring this experience into Barotrauma? Perhaps, only during rapid/aggressive maneuvers, the sub would angle strongly and force the whole crew to adapt to the rocking of the ship while they conduct their tasks/fight monsters/try to repair/etc. It would incentivize the captains to navigate more responsibly and cause some hilarious scenarios when they don't.
The one BIG drawback I see in this is the sub potentially becoming stuck at such an extreme angle that players can't move, or even possibly trapping them. But, that could also easily be prevented by setting a maximum/minimum angle the subs are capable of achieving, so no matter what players can always at least walk around, even at its steepest angles.
Oh, AND, it would let nimble captains take some of the longest vessels through otherwise impassable gaps in terrain by angling the ship to slip through. That'd be really neat.
EDIT: Regalis has replied with this: "It would be quite tricky the implement because all the structures and items in the submarine are defined using axis-aligned bounding boxes, and there's lots of logic in the code that assumes the submarine and the structures are always axis-aligned (i.e. not rotated).
Currently the submarine doesn't actually rotate in any way - when you hit a rock, we rotate the camera instead of the sub to fake the impact. It does work quite well though, it seems that practically no-one has noticed that it's faked. So it could be possible to add some subtle rocking when maneuvering the sub with the same method.
"