But the two of them are special. They open a way for Luffy. They charge against the enemy's second and third leaders. They are called Luffy's wings. Zoro is better than Sanji in power level, but it is illogical to have a big gap
Every straw hat is special. Sure Zoro and Sanji are the most special when it comes to battle, but every fucking Straw Hat is extremely special, even more special than Zoro and Sanji tbh.
Usopp still has the best sniper feats shown in the actual story, and we know he will be the best sniper when it's all done.
Nami is the best navigator there is, nobody moves around Paradise / New World like her.
Franky is absolutely broken, there's no ship out there that comes close to being as OP as the Sunny he made, if that wasn't enough, the dude has Vegapunk level tech / lasers to cut people down.
Brook is a fucking skeleton who can control his soul out if his body and was a King of Rock.
Robin is the single most important character in the fucking universe for both the Pirates and the World Governament.
Jinbei is the strongest Fishman in the world and is the best Master of Fishman Karate.
Chopper is one of the best fucking doctors in the world and he is freaking 17 years old, and he doesn't have a healing DF like Law or Marco. And he will find the cure for anything.
If you only think about fights, yes Zoro and Sanji are above the others, but when you look at the story as whole, every Straw Hat is insanely special.