One major criticism tossed at this reboot is how many things from the original were changed for the worst.
- The credits song is a lot less explosive and more pop-like than the original. This reflects the more tame nature of the reboot show.
- The extended intro changes the girls signature traits. Blossom is "the leader, always shows the way", Bubbles' "bright as a sunny day", and Buttercup is described as "rocking hardcore with a mighty roar". This upset quite a few fans who are so used to them being referred to as "commander and the leader", "the joy and the laughter", and "the toughest fighter".
- As with any revival, fan response to this was mixed to negative when the re-designs were shown. A more negative audience reaction came when it was announced that the original voice actresses for the girls were being replaced. Cartoon Network didn't even contact them to offer them a reprisal of their roles, which was seen negatively by fans. (Tara Strong was especially disappointed, as Bubbles is one of her favorite roles. She called the move "A stab through the heart", though she nonetheless respected CN's wishes and wished her replacement luck). Upon seeing the shorts and preview of the first episode, some fans stated that the girls sound too similar to one another and don't really convey their distinctive personalities to their fullest. On the other hand, there have been some fans who were glad that Strong, Cavadini, and Daily didn't get to reprise their roles. These fans felt that they ended up dodging a massive bullet.
- Speaking of the protagonist trio's personalities, those have been changed too. They act more like actual tweens and less like superheroes with childish sensibilities. Very rarely (at least in the first dozen or so episodes) do they treat fighting monsters as anything more than an obligation. The changes include:
- Blossom was formerly the most self-consciously "heroic" of the three. She had a high-minded focus on heroic idealism and civic duty, that frequently bit her in the ass. In the reboot, her penchant for order just manifests as being an obsessive-compulsive stick-in-the-mud. She also has a nerdy interest in student government.
- Bubbles's childish naivety has been downplayed, possibly because she is supposed to be older in this version. She instead acts the most like a real tween girl, complete with self-conscious body issues and a hyperactive "kawaii!" attitude.
- Buttercup now acts likes a lazy, tough-talking, prankster tomboy. She used to be a sarcastic and self-loathing, yet sympathetic jerk, who lived only for the thrill of battle. The change seems especially egregious in "Man Up II", where she chooses to collect bottle caps instead of leap into the fray. Yes, Buttercup, the definition of Blood Knight, would rather collect bottle caps than do battle.
- Likewise, many did not appreciate Professor Utonium being flanderized from a Good Parent who occasionally made mistakes and learned from them to a full-blown Bumbling Dad Manchild who often ventures into Adults Are Useless and even Lethally Stupid territory (despite being meant to be a brilliant scientist), apparently just for the sake of making him more “humorous”.
- Voice acting-wise, Natalie Palamides as Buttercup is seen as a letdown compared to Elizabeth Daily. While the new voices of Blossom, Bubbles, and Princess are generally seen as serviceable at worst, a number of fans have criticized Palamides for trying too hard with Buttercup's Tomboyish Voice, to the point of sounding too deep and surly to fit the character.
- The brand of humor the show seems to be going for focuses a lot of girl-related things. This hasn't gone over well with older fans who cite that the original series tried its darndest to avoid becoming a Girl-Show Ghetto and to appeal to everyone. The original was explicitly a superhero show with female leads.
- Ms. Bellum was Put on a Bus due to, according to the showrunners, "not fitting in with the message they wanted to convey on the show". Older fans reacted negatively, calling the showrunners out for hypocritically judging her based on her looks while arguing that Bellum was a very intelligent and capable woman who kept the Mayor's antics in check, her role as the Only Sane Woman while being a role model and source of advice to the girls. They felt that the actual reason for Ms. Bellum's absence is the mere fact that she is a Ms. Fanservice — a trope which has been increasingly viewed as sexist and un-feminist in the second half of The New '10s, regardless of the Ms. Fanservice's actual presentation as a character beyond just her visuals. This got even worse when she failed to return after over a thousand days had passed since the episode of her departure, making it clear the writers never intended for her to return.
- Some viewers aren't pleased about the show taking the Teen Titans Go! approach of doing things. There were lots of slice-of-life plots, with only some superhero stuff added. Others are glad that unlike the Titans, this was not a Sadist Show.
- The violence was toned down, despite the girls probably being older. If the girls ever do hit anyone, a Hit Flash will often hide the impact. It doesn't help that they have new Hard Light powers in this show, which means that they will be doing most of the attacking than the girls themselves.
- The Narrator was an integral part of the original series, to the point that an entire episode was centered around him. He is rarely present in the reboot.
- Mojo Jojo no longer goes on the long, redundant rants he was most known for, as well as suffering severe Badass Decay. While he did have plenty of comical traits and his fair share of bumbling moments in the original, he was still one of the toughest and most formidable of the girls’ enemies who came close to destroying them on multiple occasions. In the reboot though, he’s been reduced to little more than a Butt-Monkey and a borderline Harmless Villain and Friendly Enemy, who is more of a nuisance to the girls than their undisputed Arch-Enemy, highlighted by their numerous Enemy Mine moments.
- To a lesser extent, HIM losing the echo in his voice, which practically dilutes how scary and outright menacing he was in the original show.
- In the Brazilian dub, the line "Sugar, Spice and Everything Nice" was a direct translation that was used up until the reboot, and as such, had no rhyme between "Spice" and "Nice." When the reboot was released to Brazilian audiences, many felt insulted to hear the line being translated to "Sugar, Spice and Everything Awesome" just to keep that little rhyme on the intro.
- The phone was changed from a toy phone to a modern day smartphone, which was perceived as another attempt at relevancy.
- The art style in general has changed between the original and the reboot. The background characters in the original were based on older cartoons from the 40s or 50s, both in art style and character design. This style befit the Retro Universe in which the original took place in and gave the series an ageless quality. The reboot however uses contemporary character designs which more resemble something like Clarence or Steven Universe, which immediately dates the series as a product of the New 10s. This also makes the few characters that use the old style (like the girls and Professor Utonium) stand out. Part of the fandom claims that these changed do not detract from the show all that much, and help the show to feel more up-to-date. The other part of the fandom claims that these changes ruin the feel of the show and do not hold up to the original. On a completely different side of the argument, quite a number of fans wish the series used the Dance Pansted art style instead. Though that style was not universally popular.
- The lack of the other main villains has also been a sticking point. Of the originals, only Mojo, Princess, and HIM have received substantial screen time. The Amoeba Boys got one episode and weren't seen again (their voice actor, Chuck McCann, died on April 8, 2018, which resulted in their disappearance). The Gangrene Gang, after a few cameos, likewise got one episode to themselves very late in the third season. While Fuzzy and the Rowdyruff Boys only got cameos at best (the latter not even voiced). Sedusa wasn't used at all but considering the show's hard stance on voluptuous characters (to the point Ms. Bellum got Put on a Bus), it's generally presumed the network wouldn't allow her to be used for shallow reasons.
