I don't understand why so many MMA fans hate professional wrestling so much. Yeah, it's fake, but it's also an entirely different product.
Admittedly I'm a former WWE fan but I stopped watching around '07 or '08 when they decided to go to the "Sesame Street for big kids" route. Today it's just too childish for me and I enjoyed the darker storylines. It's MEANT to be fake, for crying out loud. I can certainly still appreciate the athletic ability of many of these guys and the hard work they put in to their craft.
Regarding the topic who which pro wrestlers I think could have succeeded, I think Kurt Angle is the most obvious choice. Honestly he probably could have been the LHW GOAT if he started training at a young age and developed some solid striking to his already excellent wrestling and submission fighting.