Those kind of statements were not made for anyone else. Yet those kind of statements don't put Sanji over anyone else, either.
Why is Sanji more important? Because he was called wings? So was Zoro, directly by author, even.
Because Luffy said he can't become PK without Zoro? Why'd he need to say that to someone who is always by his side? Hell, Luffy never said it to Robin but she is a necessity for Luffy to become Pirate King.
I can straight up say Zoro is far more important because he actually does a lot more on screen to keep Luffy in check, focused and helps him become a better leader. And he has directly saved Luffy from death more times than any other crew-mate, as well.
But I'm not.
Every nakama helps different way, every nakama gets different portrayal, hype and words of importance. Sanji being called wings or the statement in WCI gives him importance, but it is irrelevant to other crewmmates. It does not give him importance over them.