And furthermore... even if you could enclose the gimbal & camera in something crash proof still having them moving freely, the momentum of those parts in a sudden stop (crash) will damage them.
I'm building one on a carbon fiber filament 3d printer. I'm am building it to be extremely rigid, but to allow the camera to have full motion and for the guard not to block most angles, if any at all. So far I have built the structure to hold it on the nose of the aircraft. It locks in place extremely hard and needs a tool to pry it off. . I have kept the front sensors unblocked by at least 90%. I have enclosed the back, top and sides and the bottom. These enclosed areas extend only to the point at which the camera will not see them. In essence you are getting a super strong sun shade, that will not move or break on impact
Yes, if something like a tree branch got in, or a protruding rock, there will be issues, Or as said earlier, just the impact force can damage the gimbal.
I could add the option of putting a highly transparent fiberglass plate across the front of it. This would make it physically blocked from direct impact in all directions, but not indirect force.
My Experiments, so far are promising. Full motion, no visual block, additional sun blocking. I believe it offers at least a 65% reduction in stopping gimbal damage without the aforementioned fiberglass/clear front block. It would offer at least an 80% reduction in physical contact damage with the transparent fiberglass front attached. I suspect a minimum of 20% damage would come from the shock of impact to the drone at any angle.
When I fly with my earlier guard derivations, I feel much safer. Nothing can hit the face of the camera or the gimbal motors unless an object gains direct access into the guard box. I have crashed a lot. Most of my damage came from direct hits to the sides or to the edge of the camera as it flopped around and hit things on the ground.
If you are willing to buy those flimsy prop guards that are sold for so many mavics. I would think A pilot would definitely consider buying extra gimbal protection. Just like the prop guards, it can't offer total protection. But with a plastic fiberglass front, you would nearly have complete protection.
I'm gonna have to get some insurance and test this thing sooner or later.