As talented an athlete as he may be, he would get his ass beat by the heavyweight champion. We want to see the baddest Mo-Fo on the planet. We don't care if one competitor weighs more or is taller or is pumped full of designer drugs. That's the kind of freakish gladiator warfare we want to see. No one wants to watch a bunch of sports figures who aren't performing at their potential.
Most professional athletes are already freakish.
If you are over 7 feet tall, you are circus sideshow material. Same goes with a 400 lb. lineman. Yet, we get all in a huff when someone's bloodstream is coursing with horse hormones. So if God makes you a mutant, fine. It's time for a new era of sports excellence.