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.
I think you pretty much answered your own question. I believe more MMA fans would appreciate Pro Wrestling if it still resembled the hardcore, rated R style of the WWF attitude era. I was a HUGE WWE/F fan before getting into MMA, and when I saw Kane make his debut with a huge titantron explosion going in and choke slamming Undertaker after he just finished dominating a bunch of people, that was one of the most exciting things I have every seen in.my life, real or fake. But now, it has taken a much more cheesy route, trying to appeal to a young audience while still trying to clinge on to the old demographic. Around 2007 was when I pretty much was fading away from the WWE, but when Chris Benoit had his incident, that was pretty much the nail in the coffin for me (no pun intended).
But to stay on topic, Kurt Angle was actually supposed to fight with the UFC back at UFC 10, but things couldn't get worked out as far as scheduling. I think if they had been as active back then as they are now, he most certainly would'v been a great MMA fighter.
Shelton Benjamen is another guy who I would'v givin a solid chance at an MMA career. Very strong and explosive athletic guy, he wrestled at Minnisota and had a pretty solid college career, helped out with Brock Lesnar.