I don't really care if Zoro faces King or not, but one thing for certain is that is his rematch against Kaido is inevitable.
Enma still is too much of a factor for it not happening. As Kawamatsu stated, "the soul of the owner still lives inside the katana even after the owner's death." Also, he still has a black blade to forge this arc and I don't think it would hold much significance if it's forged against King or outside the Wano arc.
The Wano story has been told through Luffy and Zoro, whether they are together in Act 1 or their journey paralleling with each other in Act 2, learning about the truth of Wano and the civilians had to endure (Tama, Yasuie, Toko, Hiyori, Hyogoro, Ebisu civllians).
Oh yeah not to mention the silhouette from 1004 is probs Hiyori, a princess who has a bond with Zoro and princesses usually ask Luffy for help (Vivi, Shirahoshi, Rebecca etc).
We also have never seen Zoro have such personal attachment to the arc's characters, with him getting the angriest we have seen of him twice in one arc (Yasuie's death, Kiku's arm), and have such motivation to fight the main antagonist (as vivre card states he leaves the main antagonist to Luffy and this is the first time he broke that rule).
If the future WSS that wants his name to reach the HEAVEN, his legacy at the Land of SAMURAIS need to be greater than just defeating a commander with 0 hype.