Kuzan is more of a threat to the government with his knowledge and him being able to successfully sabotage the WG and Marines behind their backs plus the marines knowledge of him working with blackbeard..
Mihawk is less of a threat since they know he dont do much and sits on his island, but he does hold a worlds strongest title which is no easy feat to achieve and the other two with those titles being Whitebeard and kaido, both have one of the highest bounties we have seen and probably on record..
id say IMO Akoji has the potential for a higher bounty but his movements so far havent been of that much threat whereas Mihawk has a title and is known to be super Strong so anyone that can take his head has got to be insane, (this is assuming its increased since his frozen bounty while being a warlord)
Mihawk is less of a threat since they know he dont do much and sits on his island, but he does hold a worlds strongest title which is no easy feat to achieve and the other two with those titles being Whitebeard and kaido, both have one of the highest bounties we have seen and probably on record..
id say IMO Akoji has the potential for a higher bounty but his movements so far havent been of that much threat whereas Mihawk has a title and is known to be super Strong so anyone that can take his head has got to be insane, (this is assuming its increased since his frozen bounty while being a warlord)