It's like movies, could anybody other than Al Pacino have played Tony Montana? The answer to that question is irrelevant, just making a point. You have to think about the characters and pushes on a wrestling show like a character in a movie.
WWF tried to get some random guy to play Razor Ramon after Scott Hall went to WCW. That could never work. You need Scott Hall for play Razor Ramon.
Could anybody have been The Rock other than Dwayne Johnson? The answer is objectively no.
So that's the question really. Could Sean Morely have played Triple H? I don't know for sure but its not the craziest shyt I ever heard. They have similar looks, similar in ring styles and he probably could have talked the way Paul talked too. It's not that far fetched.