ZKK was never gonna happen dude, the way post skip trajectory was and One Piece in general is. Oda was never gonna have Luffy's biggest obstacle and by far his most important opponent at a pivotal point of the story, fed to Zoro. Oda would literally be bleeding through every pore of his body just drawing that. You could kidnap Oda and use that as a torture tool.
I always said this back then, ZKK is what's best for the story but it's not happening, not a shot in hell, we are in the Luffy show. Anything that threatens Luffy or even takes 5% of his shine, gets shot down.