Fortunately, He-Man's frequent disregard for physics and logic put him over the top in a match like this. That and the Sword of Power is a nice trump card when it's clear the weapons will play a factor in this fight.
But your OP makes a great point; HM's rogues suck balls (more powerful incarnations of Hordak and Skeletor notwithstanding). I'm convinced the only reason he isn't considered a high herald is that he has to constantly play down to his competition, so to speak.