Why? Sakazuki was sillhoute and last introduced he ended up the strongest why wouldn't greenbull? because hes sanji opponent stop living in denial its clear what oda intention for him are 
As for "Feats" I can do the same thing lets wait for more mihawk feats because clearly Shanks>Mihawk

As for "Feats" I can do the same thing lets wait for more mihawk feats because clearly Shanks>Mihawk