I'd like to see if a 1946 Joe Walcott and 1950 Ezzard Ezzard Charles could do better against Rocky than they did in 1952 and 1954. I know Charles wasn't a Louis "victim" but still... Also the giants like Primo Carnera, Buddy Baer, Abe Simon and Max Baer would be interesting fights. Marciano vs Galento might be a fun slugfest between two short crowding punchers.. Conn could certainly give him some problems for a while.
Hard to imagine anyone doing as good as Louis against Galento, Carnera, Baer, Schmeling, Braddock, Conn, Walcott, Sharkey, and more.
Max Baer would have put Marciano on the floor and kept him there. Rocky was hurt and dropped by punchers not in Baer's league. Marciano has the most over-rated, conveniently-timed record in the history of boxing.
The bottom line is no. The timeframe and the schedule would have been impossible for him. Or pretty much anybody else for that matter.