In any event, I would prefer Zoro to have it.
That said, I don't think Oda has done a good job as telling us why he should. The cool factor is undeniable, and there's that symmetry of other legendary pirate captains having crew members with CoC, but when it comes to Zoro specifically, I don't think what defines him as a conqueror is clear. Because I don't think it's his ambition.
Zoro's desire to be the strongest swordsman in the world has nothing to do with him wanting to conquer anyone or anything.
Not too wax too poetically but I think what all the known conquerors have in common is not merely ambition, competitiveness or drive - but an innate desire to live life completely on their own terms, however unreasonable or downright delusional, thereby in essence conquering life itself.
If that sounds crazy, I ask you which of them isn't a little crazy? I've complained about there being too many people with CoC, but I could not deny that, at least, perceived requirement is met by Garp and Don Chinjao among others.
I think Zoro's desire to conquer is not something one has to overthink. He lost his best friend to death. Now he will conquer the underworld itself if it means to protect those he cares about. King of Hell and Asura should imo be exstremely power CoC moves on par with Kaidou's attack power, i.e. capable of killing him.
I went off on a tangent there, but the bottom line is that though I can accept Zoro may canonically not have CoC (doesn't bar him from unlocking it still), I definitely think he should.
