Quarry was proven against big punchers and he could also fight on the backfoot and counter punch. Frazier is not that proven against big punchers and he can't fight on the backfoot. Which means trying to swarm against bigger opponents who hit hard is a more dangerous prospect. I'm not saying Frazier wouldn't win but he's never actually beaten any big imposing punchers before so this would be a bit of an unknown quantity for Frazier.