OK guys, saw the movie a few more times. Still love it to bits but now I notice the movie does indeed have one flaw: when Luke becomes one with the Force his prosthetic hand vanishes along with him. I think it should have remained in the physical realm and dropped.
I mean… I guess. I don’t think we know enough about Star Wars’ prosthetic limb technology or the force to make a final judgement either way. I think if his hand did drop, it would’ve totally ruined the tone of the scene. It would come off as a joke, and that certainly wasn’t the time for jokes.