Zoro and Sanji

Sanji is a more developed character than Zoro, he has more personality, but their rivalry is just a gag that the fandom took way out of proportion. Oda never depicted them as equals, never will. One is a fighter, one is a cook. Even during the time skip, one trained with the world's greatest swordsman, the other kept running and wanting recipes to be a better cook, making them both develop in a way to reach their respective dreams.

Acting as if they were equals is just headcanon and people wanting to believe what they want to believe. You don't have to be the strongest to be a good character. Actually from the way Oda writes the story, Luffy, Zoro and Nami are the main 3 protagonists, followed closely by Usopp and Sanji, then the rest.

/r/OnePiece Thread Parent