The thing is that Zoro's dream would be better to fit a main shonen character like Luffy honestly... He would need more screentime and more opponents, more character depth and struggle (Luffy and Sanji got more of that for example, until now), both emotionally and combat wise and thats why i think Zoro needs to be someone "special", he can't be a random dude, there is when the "Shimotsuki" thing comes, by doing that Oda adds to Zoro's character just by him simply existing, and connects him to other characters, places and mores
Sometimes i think Oda could've done differently with Zoro instead of putting him to get trained by Mihawk but as i said this would require Zoro to be a protagonist for example, but in a sense Zoro's whole life revolves around him and Kuina, so the amount of content Mihawk vs Zoro will have will give a complete new shine to Zoro's character.
Imagine Mihawk vs Zoro having like 20~30 chapters length, with a lot of flashbacks between them during the timeskip, flashbacks from every single fight Zoro had, flashbacks of his childhood and several things we don't even know about, it would be basicly something like a complete "Zoro's arc".