- Arc Fatigue: It happens after the wedding chapters, which seemed that the arc was going to end, and was actually the beginning of the true (and long) climax. Granted, it was figured that the Big Mom Pirates weren't just gonna let the Straw Hats walk out of the island. But then you got dealing with Big Mom coming after them through the Seducing Woods, Sanji going on to bake a cake to stop her rampage, having to fight to get the Sunny moving against Perospero and Katakuri, leading Big Mom to the island where the cake is and finally Luffy having to fight against Katakuri himself in the mirror world. Seems every time the crew look to be in the clear, another situation arises. Not helped later by the fact that it'll take 10 hours in-universe time for the crew to reach Cacao Island (where the cake is being made), meaning Luffy will have to endure against Katakuri in that time frame. The chase, while exciting, feels more like padding half the time with Big Mom closing in on the Sunny, unleashing an attack, and it either getting dodged or the crew managing to knock her back and regaining the lead. Rinse, repeat.
- Ass Pull: There is a sizable camp of fandom who are understandably pissed that Jimbei is yet again being delayed from joining the Straw Hats full-time due to a last minute hitch in the plan just as the story arc nears its close, with some believing Eiichiro Oda deliberately yanked our chains, while others believe he's just trying to keep the herd thin until Wano and forgiving this because Jimbei is technically like Vivi now — officially part of the nakama, but not actively part of the crew.
- Base-Breaking Character:
- There's quite a bit of controversy surrounding how Pudding was handled. While her reception was fine even after she dipped into a Hate Sink following the reveal of her true colors, the issues start at the wedding. Sanji, unable to keep his lust down even for a woman he knows is eager to kill him, blurts out a compliment toward her Third Eye once he finally sees it, pacifying Pudding due to her Freudian Excuse regarding the discrimination she's suffered for it. For some (see Jerkass Woobie below), this redeemed Pudding. For others, the Freudian Excuse feels too sudden and contrived (especially regarding the criticism her eye apparently got from Big Mom, which is extremely out of character given her established love of her exotic and lifelong goal of creating a discrimination-free utopia) to take seriously, and simply allowed Sanji to dance around the lesson of being too weak-willed around pretty women. Her later Tsundere characterization is either hilarious, or a waste of time during the final period of the arc that has dragged on for too long.
- The Vinsmokes ended up being rather polarizing. Introduced as straightforward Hate Sinks (aside from Reiju), they are lured into a death trap by the Charlotte family and end up in a sort of Enemy Mine with the Straw Hats. For some, they had an enjoyable Sentai motif, and the brothers' earlier behavior was mitigated by the revelation of their genetic modifications by Judge. For others, the Vinsmokes were portrayed as too one-dimensionally evil to swallow the sudden shift in portrayal from co-antagonists with the Charlotte family to semi-allies, and criticized their relationship with Sanji for being too detached from his characterization within the current story to the point of feeling inconsequential.
- Broken Base:
- The Luffy vs Katakuri fight, mostly regarding the ending. There's conflict regarding who should actually be considered the winner; Luffy fainted first, but Katakuri stayed down while Luffy still had just enough strength to walk away from the fight afterwards. There's argument over whether or not Luffy even should have been able to beat Katakuri in the first place, given the latter's enormous bounty, clear superiority in Haki, and fairly one-sided domination over most of the fight, while defenders argue that Luffy's past struggles have required him to build up greater stamina and point out that Luffy's Gear Fourth attacks have a greater damage output when Katakuri isn't able to avoid them outright. There's also the conflict with Flampe that leads to Katakuri stabbing himself; proponents appreciate Katakuri's sense of honor, growing respect for Luffy, and his maturity after the previous time his mouth was unintentionally exposed, while opponents found it forced (similar to the issue with Pudding) just to make Katakuri weaken himself.
- Given that the arc (particularly in 2016) focused heavily on Sanji, how well was he handled? Some feel much more sympathetic toward Sanji after learning about his hellish childhood with the Vinsmokes, and found satisfaction in showing off how strong and reliable he'd become since then by saving his bawling father and baking a cake to stop Big Mom's tantrum. Others found the initial Rescue Arc too similar to Robin's from Enies Lobby, and those who have been disappointed by Sanji's New World track record in battle weren't pleased to see him go through the arc without a direct fight.
- Evil Is Cool: As a major villain of this arc who broke a new record of the highest known bounty at the time, Charlotte Katakuri shows to be much more composed and competent than all of his known siblings, having strength and honor during his actions. His fight with Luffy is also memorable because of his skilled technique, his overpowering attack, and his honorable side, shown when he berated his younger sibling, Flampe, for trying to disturb a fair-and square fight, before showing his fanged mouth in front of everyone to let down the burden brought by his seemed perfection. His childhood memory also showed his protective side that he covered his fanged mouth not because of its hideous look, but because of Brulee who was harmed by his bullies since they weren't match for Katakuri, so they scarred his most beloved sister instead. It's no wonder why Luffy shows respect to Katakuri by the end of their fight and covered Katakuri's mouth with the hat Bege had given to Luffy.
- Harsher in Hindsight:
- Sanji reacting hilariously to Duval's (somehow) similar-looking face now doesn't seem so funny anymore once it was revealed that his abusive father Judge had been relentlessly looking for Sanji ever since he ran away. Having Duval around gave him a form of protection, and now that Sanji fixed his face, Judge was able to find him. Imagine if Judge found Sanji before the Sabaody Arc happened...'
- The iron mask Duval wore around his face adds another layer to the above when Judge had an iron mask locked tight over Sanji's own face after deciding I Have No Son!.
- This arc was meant to be "The Year of Sanji" and bring him into the spotlight. In practice it puts him through a Trauma Conga Line, suffering from his abusive family who want him for a forced political marriage and having no choice but to betray his crewmates once they come to his support. The last chapter for 2016 even ends with him in utter despair as he overhears that Pudding and Big Mom plan on assassinating him and the rest of his family, meaning all the sacrifices he's made will be all for nothing. Fortunately, 2017 is the true unofficial year of Sanji, as he not only managed to save his asshole family, but also regained Pudding's confidence, and managed to talk down to his father, who made everybody's lives hell. Not bad for a Straw Hat who spent most of the early chapters as a hostage.
- Lola believing that her mother, Big Mom, would help the Straw Hats in the Thriller Bark arc becomes this in light of really horrifying revelations, which makes her idealism so sad...
- Jerkass Woobie:
- Big Mom Used to Be a Sweet Kid who was abnormally gigantic for a human, unable to recognize her knack for causing disaster, and suffered from a psychotic eating disorder. When she was forced to fast because the culture she lived in demanded it for a festival, it inevitably was too much for her and she took to a rampage in the one place that she seemed to belong. She and the other members of her orphanage were forced to relocate elsewhere... only for her to accidentally eat them alive in a feeding frenzy, leaving her all alone with no idea of what happened (thinking they'd simply abandoned her). She was found by Streusen, and under his poor influence, became fully cognizant of her abilities to kill and destroy with ease, then built herself up as one of the four strongest pirates in the entire world, making it impossible for anyone to dare to come against her even if they wanted to. Worse, one of her daughters furthered her rift between her and the giants by betraying a political marriage between her family and the ruler of the giants, Loki. She has since lived her life in a highly vindictive manner and now suffers hunger spells regularly, despite trying to carry out a noble dream started by her caregiver, Mother Carmel, (who was really a child slaver masquerading as a nun who never cared for her at all and was planning on selling her to the World Government).
- Pudding as of Chapter 862 is cemented as this. She started off as a kind, beautiful young lady who's revealed to be a three-eyed Bitch in Sheep's Clothing and Consummate Liar who plans to murder Sanji and his family (which is Big Mom's plan all along) in the supposed wedding. When the wedding time comes, however, a flashback shows that she Used to Be a Sweet Kid, but a lot of people bullied her for having a Third Eye and Big Mom didn't help much beyond telling her to cover it with her bangs, while also ridiculing her own daughter's eye. Thus, Sanji calling her third eye "beautiful" causes her to have a Villainous Breakdown.
- Memetic Loser:
- Charlotte Smoothie built up a fairly negative reputation over time. Of the three Sweet Commanders active at the time the Straw Hats arrived, she's the only one who didn't fight Luffy, and some lesser ranked family members have proven a more direct threat than her, provoking accusations of her being an irrelevant Faux Action Girl who was often ridiculed for not doing anything.
- Charlotte Bruleé has been mockingly named the MVP (most valuable player in the "game"), for the Straw Hats. Since most of the Straw Hats' own plans wouldn't have gone properly without Bruleé being there to be exploited for her mirror powers or taken as a hostage, and even when left alone has still screwed over her own side (such as tanking the Big Mom pirates' morale by telling them what really happened with Katakuri)...
- Vinsmoke Judge is sarcastically called "Top 5" in reference to Youtube reviewer King Of Lightning hyping him up, only to break down crying when faced with death and get utterly demolished when he tries attacking Big Mom directly.
- Unexpected Character:
- It was long-speculated that Sanji had at least two older siblings named Ichiji and Ninji, and some even guessed there might be a younger one named Yonji in the works. What nobody saw coming was an eldest sibling designated under the number zero and a sister to boot, because everyone was so used to seeing the male Vinsmoke side of the family in action via Sanji that the female side never really crossed their minds, and people are used to starting number counts at one. Oda pulled one directly from the Tite Kubo handbook in that it channeled the twist reveal Yammy was the number zero Espada. It should come as no surprise Reiju turned out to be a smash hit among fans merely due to the fact her existence was that much of a surprise to all when she debuted in the story.
- As he was mentioned to have been defeated by Urouge and stripped of his rank of Sweet Commander, Snack was speculated to be dead or otherwise. It thus came as an unexpected surprise when he showed up.
YMMV / One Piece: Whole Cake Island Arc