#1 The Miz

Now, we know what everyone is thinking, there is no possible way in which The Miz could step up to Ronda 'Freakin' Rousey, but let's give credit where credits due. The Miz is an exceptional wrestler on all fronts.
His technical ability has been sharpened over the course of his career, he is hateable, he has charisma and he is probably the best wrestler on the mic in the WWE or in the world. The man can make anyone hate him and we're pretty sure Ronda won't have a tough time hating him either.
Is this man the funniest man in wrestling?
However, this all lies on The Miz's shoulders, because it would be up to him to hype this storyline up. It would definitely sell, there is no doubting that, but the A-Lister's fabulous heel work would make a whole lot of a difference. Even Maryse could be involved.
The only downside of such a storyline is that Ronda Rousey would have to win, which would mean that The Miz would probably lose credibility and popularity. There can be no doubt though, that the greatest heel in sports entertainment would find a way to crawl his way back up.
Definitely the most realistic option of the five.