Mihawk not being relevant is not the best thing to happen to him
He exists to be Zoro’s last fight and that’s it
The only way Oda could spice things up is by making him actual opposition (a real threat) but that’s almost impossible now that the Warlord system is gone
He will either do nothing then fight Zoro and lose or do nothing then fight Shiryu and lose
Shanks fans are praying he doesn’t meet the same fate