Before regulations come into play the added weight and space requirements for the swivel will make your car unusable, the added complexity will make the car unr

Before regulations come into play the added weight and space requirements for the swivel will make your car unusable, the added complexity will make the car unreliable, the weight distribution change will make the car unpredictable. Then the swivel will likely be illegal because it’ll lacks the integrity necessary to be part of the survival cell unless it’s ridiculous (and paragraph 1 is even worse), and its disintegration would have a very high likelihood of killing the pilot, and harming spectators. If you swivel from the outside of the survival cell you now need even more hardware to swivel the entire cell, which means you need more structure to hold the car together (under up to 9G race loads) around the swivel, thus making paragraph 1 yet again worse, as you’ll have yet more space requirements, and weight distribution changes. Also it’ll likely fail on back to back turns (e.g. Istanbul’s 12, 13, 14 or Spa’s bus stop chicane).