Wrestlers and short strikers have been very unfairly treated by the rules in modern MMA.
Taller strikers are allowed to knee to the head in the clinch, and the shorter striker doesn't have any legal, damage spamming hammer weapons like that. The rules are unnaturally designed to be against the shorter fighter here.
In NHB striking like lethwei, the shorter striker is able to use headbutts in the clinch, which taller fighters generally can not do. It evens things out.
Wrestlers could obviously just lay comfortably in the guard without having to advance position or do anything to open themselves up to being swept or submitted, and headbutt their way to TKOs.
Here are 3 guys I think would do very well with headbutts:
1) Mark Hunt -- He's a great striker but sucks in the clinch because he's 5'10". Werdum, for example, kneed Hunt to the death like the midget he is. Imagine Mark Hunt, with his big head situated on 5'10" shoulders, just the perfect height to slam 6'4" guys jaws with his forehead..
2) Brock Lesnar -- I don't think this needs any explanation.
3) Daniel Cormier -- This one is a wild card. But he's great at getting into the clinch and controlling them there; he just can't do much with it other than dirty boxing because he's so short. He KOd Stipe there. In later fights, he got Stipe into the same clinch multiple times per round, just didn't land that KO shot. Imagine if he could headbutt in the clinch.. This is a wild card for me because Cormier also has a small frame and thin bones compared to other LHWs and HWs he fights; it's possible that headbutts would result in doing more damage to himself.