Bing you get the big picture
You have to remember that to me: ZKK is not Zoro vs Kaido round 2.
That's the point I'm trying to make. When I say "Zoro vs King", I'm not at all saying an encounter with Kaido is entirely unwarranted again.
A lot of my arguments are based solely on dialogue and Oda's tendency for patterns. What I mean by this is its very peculiar to me that:
- Queen turned Hybrid for Sanji, yet we've seen absolutely nothing of King's hybrid or even Marco vs King. We've seen Sanji fighting Queen at least 4 times since he started fighting him.
- King IS in fact the number 2 of the arc. However, I'm not arguing that Zoro has to have an extreme diff 1v1 purely healthy with King. The drug he is taking implies a time limit. Who also knows if Zoro will be back 100%.
- Zoro and Sanji believe Luffy can beat Kaido. Yes, Luffy fell, but announcements were made after this to tell readers, and the combatants at Onigashima, that Luffy still will defeat Kaido.
- King has barely been shown. Its not fair to make a comparison to say he's not a competent fighter for Zoro, at least one some level.
- Not even trying to bait a Zoro vs Sanji argument, but very clearly Wano is a Zoro focused arc. Zoro generally has precedent over Sanji on performing extra actions because that is just Oda and his preferences (see Zoro vs Kuma). The biggest point I'm making here is that whatever precedent Zoro has over Sanji, Luffy has that x10 over Zoro.
IF Zoro kills Kaido, it will probably be done in a way that does not make Luffy look bad, and does not elevate Zoro into Yonko "defeating" status. I.e. Luffy and the combined forces of all these fights against Kaido will have done the work, but mainly Luffy because....Oda loves Luffy lol. But yes, if it does happen, it makes way more narrative sense for Wado to be the one to do it, the other Shimotsuki blade, not Enma. Its the blade he's been mainly using for 13 years, and very clearly is more closely tied to his lore. Its also the one that very clearly should turn black first, under Zoro.
Stressing that the above is entirely my opinion.