User blog comment:Blackendedsoul/Mihawk's Strength/@comment-4182408-20110725040734/@comment-1507483-20110725075638

Simply because Mihawk isn't a lawless pirate, he is a Shichibukai. You can't simply match the titles "Shichibukai" and "Yonko" against each other, just like you can't estimate the outcome of a fight between two pirates simply by comparing their bounties.

Think about the first time we met Mihawk. He had chased down and crushed Don Krieg's flotilla, possibly because of something as small as being woken from a nap. Mihawk isn't someone who wants to be disturbed. That could be the very reason why he accepted the Shichibukai title, for Mihawk wanted peace and quiet. Needless to say, that is not what Shanks' crew is after.

I guess what I'm trying to say is this: That Mihawk is a Shichibukai and not a Yonko doesn't necessarily mean that he is weaker then Shanks. It means that they have different ambitions.