Depends on how Oda goes about it, it doesn't have to be a "is Zoro stronger than King?" kinda fight. We know he is but Zoro's seriously injured right now and depending on how severe it is after whatever treatment Zoro gets, it could be it's a big obstacle against a, hopefully, competent opponent.
So King gets the Hatchi treatment then.
Zoro vs King isn't going to be "is Zoro stronger than King?" — that went out of the window when Oda made Zoro heavily injured — instead it could serve a few other purposes:
- Demonstrate the gap between Zoro and a Yonkou's strongest subordinate.
- Demonstrate Zoro's inhuman willpower, resilience and/or determination.
- Give Zoro a training/practice opportunity for his COC against a competent opponent.
- This works best if King himself can imbue his attacks with Haoshoku, but it's also possible without it (see Luffy at Udon).
King cannot give Zoro any of these kinds of fights:
- Kaku
- Zoro is already stronger than him, so he does not need to surpass him.
- Daz Bones
- Zoro already knows how to cut fire
- Ryuma
- King would need to be an equal for Zoro. This is hard to pull off when Zoro is so heavily injured.
The only of Zoro's previous fights the King fight could be analogous to is vs Hatchan. If Zoro indeed fights King, that's what's going to happen.
I expect King to be a lot more impressive once we see his hybrid busted out and once he utilizes his sword more. Not to the extent that he'd pose a big challenge to a completely fine Zoro but that's the thing, Zoro isn't fine right now. He's injured and exhausted, I could definitely see Zoro hone his abilities while facing King while in horrible shape. Zoro beating Kaido's number 1 is a good achievement and it doesn't have to be Zoro's greatest achievement this arc to be impressive or significant, especially when compared to previous arcs instead of to recent Wano stuff.
If Zoro fights King in this state, King gets the Hatchi treatment.
Zoro becoming stronger against King is possible, but it's hard to do. Zoro fighting King while heavily injured already implies that Zoro is >> King.
Zoro didn't become stronger against Hatchan, nor IIRC against Cabaji.
I don't know, if all Straw Hats take down fitting opponents then I imagine all their 1v1 fights this arc will be significant but considering this doesn't look likely anymore, I can completely understand Zoro not taking down King and that's fine. If the fight doesn't happen, I'll simply evaluate the fight we get and look at how that one is significant. Perhaps Marco or Sanji will take it instead.
I feel like you're evaluating Zoro vs King as if Zoro in some sense as if Zoro was facing him healthy. Zoro being heavily injured
completely changes the dynamic of the fight.
@pg13: all of the above applies to your OP as well. Everything you said in your OP is inapplicable to the circumstances in which Zoro might fight King (while very heavily injured).