Luffy and Zoro got different portrayals and obvious Luffy got stronger hits, but we see Zoro get less powerful one compare to Luffy and it was enough to get him on his knees. Though again just saying this won't stop Luffy from facing the final boss in every arc, but can't say same as Zoro as Oda put portrayals of both on different levels.
King being YC lvl is quite strong especially above likes of Apoo who easily injured Zoro like that. His feats will come more, but no doubt Zoro will not take him on solo and less likely to face him if there are more dangerous threats than him like Macro for one. He might not face him which is possibility. I am just saying to look out for routes and reasonable if an supposed match-up doesn't happen.
Why nerfed and don't use his DF in a fight? Doesn't feel like King would be honorable in engaging only like that seeing he had no qualms getting best of BMP when on waterfall, so he could get better of Zoro due to his flying and Enma is non-factor if he couldn't use it when facing Apoo when giving striking chance. Don't think it will easy get to someone like that as King just need to dodge and he is fine. Just because he wants to cut fire, doesn't mean King could be one for it and plus sometimes characters don't commit to what they stated awhile back. Again not saying possible match-ups is out, but it's getting less likely looking on situations and new characters getting involve.
Zoro will have his spotlight. I never said, he didn, but it be making impact on facing Orochi's side more on taking out one of the leaders of the Faction. Thus he can possible face Orochi, Kanjuro, or T6H with the sword, so that is possibility.