So I found this interesting review of the show on IMDb. It doesn't call the show bad, but it is a bit more critical than the other two reviews there (giving the show 5/10 instead of 9/10 or 10/10). It's also notably the only review there to compare the show to Dreamhouse Adventures. I'll copy and paste it:
"This is clearly meant to be a follow on from the Dreamhouse adventure series and the movie where we meet Barbie Brooklyn. In these previous works we got to know both Barbie Robertses as honest, genuine characters who want to be their best selves while they learn how to care about all the people around them (even the nasty neighbour next door!). Sadly, there is a subtle shift happening here. The Barbie we previously knew would never have lied to a teacher to keep up appearances, or taken over the voice of her friend without thinking that she may be deceiving the audience or disenfranchising her friend. It seems her values are being tested in the entertainment industry but unfortunately, without it even getting addressed through consequences or her younger, franker self-reflection. Barbie is still empathic, but has lost a bit of her spine and self-awareness. I would say the "It takes two" series needs parental guidance, whereas the dreamhouse adventure series was fine for all ages without too much over the shoulder questioning to mediate a 7-13 year old's idea of what is acceptable behaviour. The problem is that the target audience for this franchise generally doesn't really stretch much further into the teens, so "It takes two" actually misses the mark."
I disagree with the criticism about episode 2 (the one about Barbie lying to a teacher and lending her voice to Brooklyn), but I do see that there is a shift in Malibu's character. She is still generally nice and looks out for others, though she does seem a bit more impulsive and immature, and makes more mistakes. Said review also brings up the target audience a bit. Both Dreamhouse Adventures and It Takes Two are rated TV-Y (a rating for shows whose target audience is kids ages 2-7, though 4-8 is sometimes brought up), and thus while adults might let some things slide if they're in the know, kids may not easily get that.
I decided to check out reviews for Dreamhouse Adventures on IMDb, and many of the reviews (even just the early ones) still talk about the show fairly highly. It's in stark contrast to some people in parts of the Internet who are like "This lower level show replaced Barbie: Life In The Dreamhouse? Are you serious?" I've seen a simile rivalry between Dreamhouse Adventures and It Takes Two over which is the better Barbie show. It kind of reminds me of the rivalry between the fandoms for the 2015 DC Superhero Girls YouTube series and its 2019 reboot (with said reboot handled by a different creative team), where you have one side trying to argue which show is better.
https://www.imdb.com/title/tt19178656/reviews
https://www.imdb.com/title/tt7661472/reviews