I do agree on this, to be honest.
Luffy and Zoro's conversation on Zoro's dream plus his reflections while fighting Mihawk in Baratie do point to Zoro needing to be the World's Strongest Swordsman to be up to Luffy as Pirate King; the message conveyed is that such status is the very least Zoro needs to accomplish by the time Luffy accomplishes his own title.
Zoro defeating Mihawk right before Laugh Tale also makes the most sense considering how the plot is currently going and at this point I won't be surprised if the marines go down before the final fight for the One Piece and then we move to the last clash against the Government, Imu and company. The thing with Mihawk is that Oda has placed him in a group that is obviously going to get involved in the fight for One Piece (Mihawk and Crocodile pretty much lost the whole Cross Guild's organization to Buggy's speech, right now they will be alone if they decide to go against Buggy's goal since the rest of the army is following the clown to Laugh Tale), but such group doesn't feel, at the same time, as a serious contender: the only member of it that hasn't been defeated yet is Mihawk so he's the only one we should expect to get a serious versus when the time comes (having Crocodile, Bonez, etc. losing again the way the lost in Arabasta is redundant and completely pointless).
Everything feels almost too perfect for Mihawk crossing paths with Zoro again and challenging him one last time as his last obstacle before Luffy achieves his dream of Pirate King; especially because both Mihawk and Zoro have put Luffy's goal in a highest place than becoming WSS: Mihawk admitted Luffy's dream was harder than Zoro's, and Zoro put his own ambition aside for Luffy's when he asked Mihawk to train him. Oda writing their last duel as a parallel to Baratie where everybody is watching closely at Zoro fighting Mihawk, but this time winning, would be a nice way to wrap this subplot up so the Pirate King gets his World's Strongest Swordsman.
if oda wants to insert him later, because maybe he has some connection to imu he can by all means make it happen.
Even WB ran away from fodder marines