Sanji was a failure for Germa's standards, thats what matters. He learned everything because of Zeff, who was a pirate who owned a restaurant for pirates, and Sanji then stills developing from it.
Zoro literally has no ties with Wano, even tho he looks like Samurais from Wano such as the Shimotsuki. That was one of the biggest complaints towards Zoro in Wano, he is in the land of Samurai but still feels completely indifferent to it
Why is Oda delaying Zoro's backstory so much? We already got Sanji and Luffy's, Wano just ended and we got nothing for Zoro
The answer: Zoro is a clone considered a failure and Oda is still cooking.
Imagine Wings moments that could come with this. Sanji knows what it is to be discarded as trash with your family wanting you to be dead
Luffy also doesn't seem to appreacite Zoro as he should. Zoro is like doing everything to back up Luffy and it seems like Luffy doesn't give a shit, he treats Zoro the same way he treats Chopper. Just look at how high Luffy places Sanji lol
Idk man, this is looking odd for me