I like how GSP is classified as a wrestler.
5/8 of the champs use wrestling offensively (5/10 if you count Barao and Rousey) to some extent. Calling it the dominant fighting style is silly.
If it were the dominant style world-class wrestlers would "dominate" every division. 0/10 of the champs are world-class wrestlers and that isn't even debatable really....
Cormier is the closest we have to a champ with world class wrestling. He isn't in the UFC and techincally not even the SF Champion, but he is the SF GP Champion and will be immediate contender for UFC title. Cole Konrad won exclusively with wrestling in his career. Ben Askren is the same way. While they are not UFC Champions, they are prime examples of world class wrestlers using wrestling, pretty much exclusively to succeed at a high level.