IIRC when the celebrated osprey crashes happened as soon as one engine stalled or failed the second one torqued the aircraft on its back very rapidly.
Even in the cases of Robert's Ridge, for example, when C-47s took hits and began losing power the effect was to go straight down, at least land on your belly. I dont know how 47s and 46s do it but in a UH60 if the engine starts to fail you can free it from the rotor and autorotate, yes? Hypothetically speaking, if an Osprey was in a hover over an urban area, and took an RPG hit a la the blackhawk down helicopters, instead of spinning onto its belly and suffering 20-30% KIA in the crashes, would it not want to flip on its back?
The last issue was I have had helicopters fly around me a lot in a tactical environment and it is a rare event that one flys right over your head. SO if you see one, say at 100 feet AGL, 200 yds away, and pop some rounds at it you are aiming for a flank shot and those engines are right in the way. The engines shield the airframe, from bullets,and they are the most vulnerable part.
I always thought (and someone please correct me) that the most battle resistant helicopters were the contra rotating ones, like the Sov Kirovs, as there were no tail booms and since the engines and rotors were so close together the smaller target could be armored heavier with less weight.
That being said, I think most Ospreys that go down will cartwheel or flip. But I could be wrong.