If you watch video of Schmeling (and taking the jerky quality of the frames into consideration), he had a big right hand but not much else about his skills was world class.

He was not particularly big, average jabber, no KO in his left hand. Granted, he was tough as hell (apart from when he won his world title on the floor).

He would not have had enough firepower to keep Marciano off him for 12 rounds, never mind 15. I think Marciano wins 8 out of 10 fights against Max, by stoppage but not outright KO.

The 2 that Max wins would have been stoppages on cuts