I see your point, but explanations that have been around longer than the movie don't really hold anymore. Boba Fett for example had a whole different history untill episode 2 came out.
I don't really know the answers, but I still think he was using the force to conceal his true self.
I mean, soon after he killed mace, he got up and acted like everything was ok. If he was in pain, or his face fucked up because of what just happened, wouldn't he have said something?

I dunno

I may have missed your point!!lol