If you believe that Mihawk is stronger than Yonko and let's say you're right for this time, wouldn't Zoro defeating Mihawk put him above Emperors? So let those with the dream of becoming PK have their moment.
Mihawk is as strong as an admiral/yonko. And as a matter of fact, zoro will surpass Mihawk and Shanks. So yes, zoro defeating mihawk will put him slightly above emperors
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Just look at Mihawk's Databook, he's waiting someone stronger than shanks, and doesnt matter who is stronger between shanks and mihawk because zoro will surpass them both. Meaning, eos zoro ≈ Mihawk ≈ Shanks ≈ Yonko