I think there is a decent chance Mihawk could be a conqueror and have ACoC. My point is that he doesn't have the portrayal to necessarily be a good one. At least in comparison to other top tiers. And every bit of portrayal shows that the yonko are better CoC users than mihawk.
Kaido, Big Mom, Shanks, and even Luffy wouldn't get stalled by Vista in any capacity.
Guess we'll have to wait till his big fight. I see it going 2 ways:
1. Zoro is about as strong, or even stronger, than mihawk, and is ready to face him now. Making Mihawk in between yonko and yc1
2. Or Mihawk is in fact stronger than Shanks, and Zoro will need an arc or 2 before facing him.
I could see it going either way. Reminds me of when sasuke fought itachi w/o achieving mangekyo. Doubt much of the fandom thought he was ready at that point, much like zoro now. Guess we were wrong