Zoro faced Kaido and was on the rooftop while Sanji wasn't
Zoro faced Lucci while Sanji bubble gunned Kaku
Zoro uses conqueror's haki and coating while Sanji doesn't
Zoro's attack resulted in kaido mocking him right before targetting his attention luffy again.
His skirmish with kaido resulted on the necessity of Deus ex machina medicine + 2 advanced forms of haki to defeat a non awakened non conqueror non advanced haki user commander.
Killer was in the rooftop too, does it mean he is closer to captains than underlings?
All east blue 5 will have CoC, oda already hinted that in onigashima.
The longer it goes, the more obvious it shows that zoro will always be closer to sanji than to luffy.
Nika importance and strength will keep skyrocketing while his underlings try to catch up.