Hughes was at the time the best MMA fighter on the planet not named Fedor and it took the GOAT to beat him and take his place.
Don't hold against GSP the fact that he was/is a pioneer that is the model for the modern MMA fighter.
WW is also >>>> MW as far as talent pool goes and it's not like Anderson Silva didn't fought his fair share of bloated WW too lol
(Maia, Cote, Nate The Great, Nick fucking Diaz (Silva had a worse showing than GSP AND still got caught for steroids, what a loser lol) and Okami)
Penn was the GOAT LW when GSP fought him but was a former WW champ too.
Henderson isn't a bad victory, but GSP's victories over Hughes, Penn and Shields are all >>> that one. Same goes for Belfort.
And before you even think to bring Serra to the discussion: Chonan, Takase, and who the fuck is Azeredo?