Here is the deal.
Sanji has great character development once again, with a new storyline, about his fear of losing his humanity.
Oda likes to experiment with his character, with his relationship, with his father, Pudding, Luffy, Nami whoever.
Zoro on the other hand ,has no character development, he has to look perfect for the zorotards .... who couldnt give less of a shit about the story, just the fighting. Dragonball tourists, I call em.
Zorotards have the Judge mindset of wanting perfect soldiers, and not characters.