Can I just say I feel like Luffy’s maturity level rose significantly in this Whole Cake Island Arc. From the start Luffy’s only goal was to bring Sanji back and escape. If it was any other time Luffy would think that he’d have to take down Big Mom first. Then although he got split up from the rest of the crew they regrouped quicker than usual. The Luffy before would usually get caught up before regrouping close the the end of the arc. Luffy also excepted Nami’s help which I think is a huge step. Ever since Luffy has reached the New World he’s taken on more help and gained more allies, realizing he can’t do everything alone. The fact Luffy said he’d wait for Sanji instead of storming the castle is also a big step. Although he eventually did wreak havoc on the castle, the moment he found out Sanji was informed about Pudding he left immediately. I know I’m kind of repeating myself but, Luffy was mature enough to team up with someone he didn’t particularly like for the greater good. This has gradually become a theme in the series. And lastly even when Luffy was caught up in fights he still worried about the others and seeked out ways to assure their safety.