User blog comment:Keekian/Will OP be better if Luffy was smarter?/@comment-24769684-20170423233738

Luffy's cooking stint at the WCI arc was meant to highlight the effect Sanji's absence had on the crew. Luffy tried to step up and fill Sanji's role, but his personality made him completely incompatible for that. It wasn't meant to highlight a negative facet of Luffy, it was there to show how much Luffy's crewmates mean to him and how he couldn't survive without them because they all have something he lacks. Meanwhile, he gives back to them as a leader, case in point being finally managing to break Sanji out of his mid-arc slump and having the balls to do pretty much the only thing that could get them out of Whole Cake Island.