Thanks for the tag.
WCI was, by far, one of the worst arcs this series has ever produced. It was too ambitious in its scope and intended themes, meaning that it achieved none of its goals and only served to frustrate the audience with the sheer amount of BS, absurd plot conveniences and banal character interactions that ultimately went nowhere.
Sanji's arc was a chance to see him grow and change, becoming more than a chivalrous pervert who doesn't waste food. Oda established conflict between Sanji and his father/brothers over their treatment of women, their elitism and their unethical use of science. However this conflict went absolutely nowhere, somehow degenerated into being all about Zeff. Cosette, the victim of brutal domestic abuse and Sora were completely forgotten and Sanji somehow forgot that he had issues with how the Vinsmokes used their scientific prowess to create clones and use them as human shields. His interactions with Pudding degenerated into cheap gags, and the so-called 'master actress' became incapable of even the simplest tasks, fainting, swooning and shitting the bed like Boa 2.0.
I've never been Sanji's biggest fan, but I was hoping to be proven wrong and see character development as he came to terms with his past. Nope. Sanji did not achieve closure, he has not spoken a word to Judge or his brothers about Sora (do they even know or care that they have a mom?) and he has utterly failed to convince them that cooking is a worthy profession or that he can surpass them on his own merit. The Vinsmoke arc was utterly garbled, confusing, and had no clear direction after the tea party, resulting in some very forced and awkward interactions between Judge and Sanji, and his brothers still thinking of him as a loser and a failure at the end of the arc. Which makes you wonder, what the hell was all that for? What a waste of time.
This isn't even getting started on the rest of the bullshit with the BMP, who have achieved the dubious honour of actually being worse than Hody and the New Fishman Pirates.