The mink medicine plot isnt a valid excuse to remove completely a character if Oda require him later to do some extra work like Chopping Kaido over the flower capital. Scabban were totally defeated and Oda reused them, same with Robin (collapsed coudnt do anything but she is fine right now, same with orochi, same with many other characters fighting inside Onigashima (marco exhausted defeated and yet Oda is still using him for something). If Oda want to go with the narrative that Kaido has to die, no matter if the medicine run out the only one that can achieve the feat of Killing Kaido is Zoro. Let see where the story is aiming. In my opinion no doubt Zoro will have 1 more say with Kaido.