We shouldn't forget that MOTUC represents ONE continuity that has elements from the others. That means a barbarian He-Man won't have the exact same story as he had in the minicomics. It is unlikely that he will be described as fighting Skeletor, Beastman and Mer-Man. He will probably be fighting some other villian (Prahvus?) instead.
The Barbaric He-Man will probably represent a post-Grayskull dark ages that occurs between ancient eternia and the time of Randor with its own heroes and villains.