If Mihawk retains the highest bounty under the current Yonkou, I think this would mean he's meant to sit at the current top with Akainu (and probably the God King the way things are going). Otherwise if Aokiji (an Akainu victim) takes even that claim from him, I won't buy into it anymore. Mihawk would be a legit top tier, but he's just in the mix with the rest.
Let's see how it plays out.