These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Cure Ace herself. Is she a really badass and awesome new addition to the team or a badly shoehorned-in character who makes no sense? Is her being noticeably older than the Cures when transformed and noticeably younger when not appealing or off-putting? Is she a cool Aloof Ally who just wants to help the girls to get stronger however indirectly or is she a smug and condescending girl who does nothing to help the Cures but takes the credit anyway? Fans seem to be rather split on this.
Mana is either awesome and refreshing for a magical girl protagonist or a Mary Sue and a spotlight hog.
And of course, the whole season itself. Fans are so heavily divided over it.
Counterpart Comparison: To Aikatsu, which is an idol anime and aired four months before the show. The two have many similarities, namely the shared card suit motif, and each has a red-ribbon blonde-haired girl.
Recently, there have been crossover fanarts featuring the two shows, with Regina and Ichigo being the most prominent.
Draco in Leather Pants: Regina quickly became this for the fanbase. In hindsight, they were onto something with that.
Alice's butler, Sebastian, is also quite well-liked. His stint as "Cure Batman" in episode 25 has definitely aided his popularity.
Fan Dumb: People accused the characters of being "too special" and therefore Mary Sues before the show had even aired, based one one line descriptions in leaked pre-show information. The accusations continued during the show's first few episodes, with Mana, who took heat simply for being athletic and the president of the student council, and Alice, who hadn't even been formally introduced getting the worst of it.
Foe Yay: Regina and Mana. Hammered home in episode 22, where they're shown sharing a bed in a rather romantic-looking manner.
Aguri's body is set on fire when she transform into Cure Ace. Portgas D. Ace had fire as his devil fruit powers. Cure Ace is voiced by Rie Kugimiya, who voiced Shana with the blazing eyes and flaming red hair - Cure Ace has these, too. Ace's weapon - no, not thatAce - is called "Love Kiss Rouge". The first red Cure was Cure Rouge, who had fire powers.
Alice has been drawing comparisons with Batman. Then in episode 25, her butler Sebastian makes a Batman-like Cure costume. And he was supposed to be the Alfred stand-in!
Iron Woobie: Makopi, whose Woobie-quotience is enough to break the Woobie-o-meter several times. She's a refugee from a magical kingdom which was destroyed down to the spiritual level. She's a questing-knight in search of her lost queen, who might have been dead all along. She's a Magical Girl Warrior fighting enemies made of the evil-defining aspect of humanity. And before she meet the other Cures, she's without allies except Davie.
Anything that can be applied to Makopi can be applied to fellow Knight of Trump Jonathan Klondike, known on Earth as Joe Okada. The poor man doesn't even have a fairy.
Alice is already drawing comparisons to Batman, what with being a rich "superhero" with a skilled butler.
At one point, during the ending Dancing Theme, the camera focuses on Cure Diamond during a rather... silly-looking part of the ending choreography. This led many Pretty Cure fans to believe that this meant Rikka was a bad dancer. Thus, the "Rikka dancing" meme was born.
Speaking of Rikka, fanartists seem to like portraying her as a Yandere towards Mana, usually with Makoto (or more recently, Regina) involved. Interestingly, this is what they did to the last season's Reika, who also had blue hair and had a very close Cure friend.
Narm: When a Jikochuu is made from a Victim of the Week, the way the heart bursts out of the person's chest resembles the visual effect when a cartoon character is madly in love with someone.
Not to mention that their appearances are as a rule more stupid/cute than actually remotely scary at all.
Nightmare Fuel: The destruction of the Trump Kingdom and the fate of its citizens. The younger kids probably won't understand what it's like to lose your home and your folks, but it makes the older kids (and the older audience) cringe.
Periphery Demographic: Adult males. Then again, given that there was a "marketing" paper that listed the "main target" as 4-to-12-year-old girls and 16-to-35-year-old men, this is an arguable subversion.
Regina is also becoming this for certain Mana/Rikka shippers, some of whom have complained that the focus put on Regina and Mana's interactions necessitates Mana's devoted childhood friend Rikka, who was already getting shafted somewhat in favor of Makoto, getting pushed aside even more in order to give focus to Mana's growing relationship with Regina.
And after Episode 26, Ira is getting a lot of heat from Manax Rikka shippers.
Fan-Preferred Couple: Mana/Rikka was a popular ship among fans before the show even aired. When Mana and Rikka were shown to have a great deal of Les Yay between them in canon (i.e. episode 2), the ship became even more popular, to the point of pretty much being this series' Hibiki/Kanade.
Foe Yay Shipping: Mana/Regina has become a popular choice. Ira/Rikka had become popular as well since episode 4, and became much more popular after episode 26.
Launcher of a Thousand Ships: Aida Mana is proving to be quite possibly the most shipped person in the series' history. Most of the girls that fans ship her with include Rikka, Alice, Makoto, Regina, and Aguri. And then there are jokes abound about how Dokidoki is a stealth Harem Series. Pixiv even has a tag specified for her harem (マナハーレム).
Crossover Ship: She is also shipped with previous season's Miyuki, thanks to the All-Stars New Stage movie.
Before Mana, Makoto used to be shipped a lot with the other Cures, Marie-Ange, and even Davi in her manager form.
OT 3: It is either Makoto/Mana/Rikka, Regina/Mana/Rikka, Regina/Mana/Makoto.
Ships That Pass In The Night: Marie-Ange/Marmo is this somewhat, probably because Marmo was the only Selfish member who personally confronted her. Rikka/Ira was this, with fans producing bucket-loads of fanart based solely off Marmo briefly teasing Ira about having a crush on Rikka in episode 4... and then episode 26 happened.
Shocking Swerve: Regina turning evil again and Cure Ace being someone we've never met.
They Wasted a Perfectly Good Character: While everyone aside from Mana, Regina and Cure Ace can be seen as this, Alice in particular gets the short end of the stick, as it can seem like her only purpose on the show is to use Rosetta Reflection.
Visual Effects of Awesome: Aside from the series having relatively good animation throughout, Cure Ace's transformation takes this to a ridiculous level. It's almost near movie like when it comes to the animation quality and is considered to be the coolest looking transformation in the franchise to date. See it here in HD.
Uncanny Valley: Ai-chan just looks weird, being more humanoid-looking than other Pretty Cure fairies.