I’ve seen a lot of takes that Sanji since Whole Cake Island has learned to trust in his crewmates and ask for help (even from the women). And I totally agree.
But there’s another aspect to this that I think a lot of people missed.
Sanji didn’t try to sacrifice himself.
Previously, Sanji constantly risked his life to protect his crewmates and we got a hint of why in Thriller Bark. Think back to when Zoro and Sanji were both ready to sacrifice themselves for Luffy. For Zoro, this is a moment of character growth— he’s willing to put his dream on the line to save Luffy, the complete opposite of how he was when Luffy first met him.
For Sanji, on the other hand, this is character stagnation and the audience’s first glimpse into why he has such a self-sacrificing nature. His statement to Zoro sums it all up, “Sorry, you’ll have to get another cook.” Deep down, Sanji thinks he’s expendable and replaceable. And Zoro rightfully knocks him out after that.
It isn’t until Whole Cake Island that we find out why. Sanji was told and shown repeatedly (by his own family) that he was a failure that never should have been born and was better off dead. This mentality seems to stick with Sanji and his guilt over Zeff’s leg just seems to compound it. Remember, when Luffy first met Sanji, the cook was ready to throw his life away over a damn restaurant!
Now, after Whole Cake Island, Luffy has finally gotten Sanji to see that his life is worth something (“I can’t become Pirate King without you!” “This food is delicious! It’s got all our favorites!”).
It’s just nice to see that Sanji’s showing some self-worth now.
*Theory by Mirai_no_Beederu