I think the camera angles in the Senseless Destruction campaign are really cool, maybe there could be an option to enable it in freeroam?
But where would you turn the camera and slow mo on and off? they would need binds. And you would need to manually place the camera.
The point is, it should not be that hard to do, just set the camera ahead and a bit to the side from where the car is facing, and move the view to that camera during a crash.
But you never know how much development exactly goes into that part of the game. Yes, you could just say "set the camera ahead locked view into the car and slow it down" but if you truly dont want the camera to be obstructed by mistake, or if you want to get good shots, you will need preset camera positions or to manually set one. Besides, you would need to specify what starts the cinematic camera and what doesn't. Speed of crash? fall distance? air time? etc.