Narrative shows that Zoro has to become WSS
before Luffy finds the one piece and becomes Pirate King
since if Luffy was Pirate King and Zoro wasn't WSS, he would make Luffy look bad:
Also the fact that Cross Guild is now going after One Piece and only notable fighter there is Mihawk
And we know final war will happen
after One Piece is found. That's where Admirals will fight as the strongest force of WG.
Just like marineford showed with Admirals fighting stronger opponents, meanwhile Mihawk was dueling Vista to a draw.
Admiral > Mihawk
Obvious answer.
We already know how admirals react to people capable of fighting on par with Mihawk
Mihawk was only dueling Shanks who had less than 1bil bounty
Is Katakuri as strong as current Luffy just because they were fighting on par back in WCI?