after seeing the bone movement, the first that came to my mind was implementing a system similar to how bones are set up, for the physics behaviour. if you could implement a similar editor for physics that would be amazing, letting us easily set up vehicles and belts, ropes, ect.
you choose a root object (like you do with bones) and then when you press edit you could add other physics objects to the hiearchy in a similar way to how bones work. you could then hinge or fixtate or spring those objects to each other in the editor, in a fashion similar to Phun (while paused).
i find it very tedious and blocky/unprofessional/glitchy to have to hinge a vehicle toghether at the beginning of a layout like we do now, this system would make physics vehicles a breeze. and if youre able to make boned objects into ragdolls (which would be totally awesome!!
), this shouldnt be that different.