No you can't!!! Both Sengoku and Kong are part of something bigger than themselves–the Marines. These guys fought many (not one like Mihawk when Shanks wasn't even an Emperor) top tiers, they obtained the highest position in the strongest military force in the world. Both of them are/were part of the big game, Roger himself praised Sengoku alnogside Garp, Sengoku and Kong know something about the history of the world.
Mihawk is not like them, he's an outsider, he's not part of the big game, he has nothing going for him.
I didn't say that Mihawk shouldn't be respected for his strength, but strength alone is nothing. Fujitora and Ryokugyu existed in one piece world and we never knew they were there, Oda just pulled them out of his ass, they were irrelevant to the story until they became part of the Marines (something bigger than themselves), before that they weren't part of the big game. But now they are, and we know these guys and their names. How many strong guys are out there about whom we don't even know and have no idea? Who fucking knows. Mihawk is outside of the game, he has only the WSS title which he got without defeating anybody, unless Oda wants to hype the shit out of Zoro I don't see Mihawk getting very high bounty, he's simply too irrelevant to get one.
As I've said it in other threads, power levels don't exist in one piece for me, I don't judge Mihawk or any character per say by what they showed in Marinford, just by their relevancy to the story.