I guess what bugs me about TR more than anything is he seemed "too new" at the time they were planning the monument. Like picking Cena.
However, looking at the presidential roster more carefully, the only real contender for TR's spot, and the guy I would put in his place would be John Adams - more of a Arn Anderson or Bobby Eaton type.
But then Rushmore would be comprised of the first three Presidents + Lincoln and wouldn't span the eras like it does with TR. Not much to pick from between Jefferson and Lincoln. No real contenders after Lincoln until TR.
If the Crazy Horse Monument had been done first and they were picking guys for Rushmore in the 80's, suppose FDR and JFK would be in contention. Reagan could be on the ass-end of the sculpture, I suppose.
As for the four for wrestling, I'd go Hogan, Flair, Hansen, Lawler.