The point of Zoro vs Jack would be to let him defeat someone
Why does that matter?
Zoro role is a fighter on the crew and so he fights the strongest swordsman because that's his dream
The straw hats have their roles and their roles exist to further their dreams as well.
Chopper said he'd become a great doctor for Luffy and his becoming a great doctor is meant to further his dreams well.
Since when does Zoro fights exists just so that he beats any random person
Again, If Jack is no one to Zoro's dream then why bother? Let Zoro at 100% fight Kaido. I mean this shouldn't change much right? It's Kaido. What does 100% Zoro mean the great Kaido?