I prefer Adam to He-Man. The less I see He-Man himself, the happier I am. I'm there for the world and the other characters more than I am He-Man (or She-Ra) and too much He-Man means I get to see these other lovely people and the bones of the story less while everything tends to get solved by the magic of He-Man punching stuff. The older I get the less I like He-Man himself and the more I like Adam (who is far more interesting because he isn't enhanced with magic). I'd much rather enjoy the universe I love than watch endless scenes of He-Man punching things or whacking them with his sword until they break or explode. Those are nice in moderation but what we need is a strong story and a lot of that depends on Skeletor.
The villain motivates and carries most hero stories, even if behind the scenes. It is important to have a decently constructed villain and this is where I believe the movie will fail. Langella was a good Skeletor within the confines of a pretty bad movie. Frank's attention to detail is what elevated his character to the scene-chewing level of awesome he attained. Skeletor has a lot of layers to him that make him interesting, compelling and even sympathetic. Langella knew this and spoke about it in interviews. He took the time to do the research, talked to his kids about who Skeletor was and incorporated things from his own nightmares in his quest to become the character and that's why his portrayal came across as the absolute powerhouse of the movie that elevates it from forgettable to cult classic. If we don't have a decent, believable Skeletor it's not going to end up Masters of the Universe at all-- it's going to end up Skull-Faced Hordak Clone vs Golden Boy Whacker of Stuff in 3D Explosionvision. I can read better fanfic than that.