I really think it would be an entirely different game than the rules-based MMA of today. I do not see the same fighters being on top.
For some reason, I think that under no rules, Wandy would reign supreme. He just has the brutality to make it work IMO.
For the record, I think NHB would also take the weight classes out of the mix. Would LWs even exist in the sport against such large, dangerous opponents?
Don Frye's Mustache > Kimbo's Beard