If he got absolutely shredded, I would say Cedric McMillan. Most probably won't agree with me, but I think he's the best genetic freak in bb'ing right now. It just doesn't seem to have come together for him yet, for whatever reason. If he's diced, I think he can beat Dex for the Arnold, and I think what's more important, is that the judges would give it to him.
Also, if Toney Freeman could get ridiculously cut (like Heath or Kai) and hadn't torn his pec, he'd be a multiple Mr. O.