Right, they're best friends, and as I said (and looks like you agree with me) they have a minimum gap when we're talking about power.
You understood wrong what I said about the narrative question. Let me explain: Oda is doing the parallel between Roger Pirates and the Mugiwaras. So the parallel is Luffy and Zoro <-> Roger and Rayleigh.
Let's see: I think Prime Rayleigh was a guy that was stronger even to beat a Yonkou just using Haki (Zoro WILL reach this level or even surpass it). And Roger was stronger, but not much.
You're trying to convince me with arguments that Zoro is equal or stronger than Luffy. And I'm presenting you points in the manga (and that's how mangaka works) that show for all the fans that: No. Zoro isn't stronger than Luffy and there's nothing wrong, I still love Zoro, I still love Zoro chapters, he really is the Right hand of Luffy, he is a prodigy on AdvCoC using, and he is the second man in power in the Mugiwara pirates.
But, man, it's not about me or anyone. It's about how Oda writes the story, and that can't change. The manga doesn't work how the fans want to. It works how Goda wants and that's it.