So according to this logic Mihawk and Buggy will be the final villain?
Based on ''titles'', If WB was alive as ''WSM'', Marco would be the final villain for Zolo. And Shiryu is clearly > Marco.
Easy to debunk your nonsense as we know Luffy vs Buggy won't be the final fight, even though Oda can actually make that by giving Buggy a special army, still wouldn't be worthy of final opponent too.
Why Imu and Mihawk fight SH pirates at the same time?
Mihawk is Marine Hunter and not a Warlord anymore, he can't join forces with Imu.
If its battle royal where everyone fights then Teach is final villain as we know Teach likes to come out as victor during a chaos.
WSM WB's right hand Marco was no different after Garp's attack, and Shiryu was literally laughing after delivering a mortal wound to Garp, did you see Garp laughing right after?
Without Shiryu, even Aokiji couldn't do anything until then.
Shiryu > Marco for sure after Shiryu's DF Awakening.