What is the difference? Sanji followed Luffy's orders. Zoro followed up a plan and went to Wano. The fact of the matter is, Sanji has never taken decision for the whole crew till that Dressrosa moment and he took decisions that needed Luffy to solve.
Get it through your thick skull, only Luffy, Nami, and to some extent, Zoro makes decision for the crew. Sanji was given opportunity to do it once and he didn't exactly rise to the occasion.
If decision-making and leadership is concerned, only Nami and Zoro has any dibs on the VC position.
Robin, Franky and Ussop didn't reach Wano?!