many people dont realize marciano changed his style from a one punch knockout artist slugger to a more mechanical less powerful volume punching swarmer. the change happened post 1953. I like the 1951-1952 marciano version better. The Marciano who walked through 6'2 215lb joe louis and destroyed him was rocky's best fight.
I think it depends a bit on who he's fighting. For instance, against a guy like Tunney, the wear-you-down version that fought Charles and Moore may do better. That is not to say he couldn't knock Tunney out the way he fought in 51, of course. But you get my point.