I've been aware of the theory ever since we started getting promotional material of the current arc. I like the idea, though I doubt he'll serve as the antagonist at least until the tournament is over, or until the fight between Goku and his opponent in the opening takes place. If they do go this route, I'd like to see the finale be a team effort to defeat him with all the Hakaishin helping take him down, since there's no way for the U7 fighters to take him down right now without either a new pointless SSJ form for Goku or a new form + Potara fusion.