I think SRR gets lumped up. There are weight classes for a reason. He'd have to hit and run all night and that's a tall ask with such a weight disparity. Schmeling was no mug and Sharkey had a very useful jab. At best SRR looks good for the early going before being ground down.
Mickey Walker was a helluva inside fighter he got inside Sharkey’s reach, smothered his power. Stocky, strong type - you see what happened against Schemling though. I don’t believe the type of fighter Robinson was that he could do what Walker did he’d get broken up at mid range against someone like Schemling and boxing someone as big as Sharkey - eh I don’t find it favourable.