Rockstar was shown again on a coverstory looking pretty swole lol.
And Mihawk literally has no alternative in the coming war. He's not a Shichibukai anymore. Might as well ally with Shanks while they pursue their goals. Otherwise, he's just an isolated fight machine for zoro. He needs to be tied to some faction moving forward.
Hence my reasoning for why Ben isn't Zoro's counterpart here. Mihawk clearly is closer to Shanks' equal than Ben