4 - Shinsuke Nakamura

For those who don't know, Shinsuke Nakamura does have a legitimate mixed martial arts background, as he was a fighter in Japan before he became a pro wrestler. Of course, I don't think WWE could sell a Punk vs. Nakamura match on the fact that the two have MMA backgrounds simply because Punk has never won an MMA fight, so the fans probably wouldn't buy into it.
However, the two could implement a ton of MMA stuff into their match, which would probably make for an incredible in-ring performance.
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Also, Punk and Nakamura never faced off against one another outside of WWE, so it'd be a brand new match, which is definitely something rare, especially in WWE.
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