I think it would be one of the worst moments in the story for both Zoro’s character and Luffy’s.
This is stupid as fuck
Oda had Zoro build personal bond with Yasui and Hiyori and Yasui before his death claiming defeating Orochi is gonna do nothing Kaido is head of it all and then focusing on Zoro when death or Kaido is brought up.
Kaido taking everything away from Hiyori.
Kaido saying there is no samurai quite like Oden and never will be and Tenguyama saying Oden was not skilled enough to make a black vlade and Oden himself admitting he's not skilled enough to kill Kaido.
Kaido wanting an honorable death at the hands of samurai.
Zoro looking just like Ryuma and Ryumas legend being saving Wano country from a dragon on top of flower capital.
What better way to make Zoro new Ryuma make Zoro black blade and Zoro surpassing Oden all at the same time besides Beheading Kaido??