Some fans don't want Pixar to make sequels, some do, and some don't really want them to but are okay with them being made anyway. Similarly, almost every individual unreleased sequel has a similar break between those anticipating and dreading them. That's the mentality in the wake of the much-maligned Cars 2.
Fans noticed all of Pixar's movies were all male-lead and started asking for some films starring women and girls to balance it out. Pixar has since responded with Brave, Inside Out, Finding Dory, and in a way Incredibles 2 (with Elastigirl rather than Mr. Incredible getting the "action" subplot). The fandom seems split on whether the first one is a positive step forward or not, being criticized as a stereotypical princess movie. Fortunately, the latter three did much better critically and financially, with Incredibles 2 even becoming the highest-opening animated movie of all time domestically, with Finding Dory close behind.
A more positive example: which Pixar film is the best? One might think this would have an easy answer, but because most of their output from the beginning has been well-reviewed and amassed a hugely dedicated following, you can't call one film their best without it being a disservice to all the others.
On whether Pixar has managed to get out of their Dork Age; some people feel that they have due to the universal acclaim of Inside Out and Coco and very positive reception of Finding Dory, and Incredibles 2, but others feel that they begun to get out of it with that film, with The Good Dinosaur and Cars 3 widely being considered So Okay, It's Average.
Dork Age: Afterahotstreak following their Disney merger towards the end of the 2000s, Pixar spent most of The New '10s in a rut. Most of the criticism comes from them focusing on uninspired sequels rather than developing new IPs.
As their next film, The Good Dinosaur, entered hot waters, John Lasseter, after working on the successful Disney film Frozen, caught on and decided to postpone it to save the studio further embarrassment. The next film in the roster, Inside Out, was critically lauded as another Pixar masterpiece and a return to form... and then The Good Dinosaur finally came out, barely made an impression (not helped by it going up against The Force Awakens), became the studio's first financial flop, and left many worried that Inside Out was just a fluke.
Before all of this, John Lasseter acknowledged that the studio had entered an awkward transitional period as the original creators were training up-and-coming filmmakers to succeed them, but the successors weren't turning out the kind of films they were looking for (Lasseter being the head of both Pixar and Disney also undoubtedly put a strain on his own contributions).
Their films in the second half of the decade were mostly well-received, albeit not the cultural milestones their earlier films had been and still with some gripes that the studio was relying too much on sequels (Coco being the only non-franchise film at the time). If that weren't bad enough, John Lasseter getting #MeToo'd in 2017, with the studios last two films of the decade also being sequels, only did more damage to the studio's reputation.
Do NOT refer to Pixar films as "Disney films" around Pixar fans. Their movies are considered a separate group of movies from Disney's, despite being released by Disney and starting with the Disney Vanity Plate before Pixar's own.
Joe Ranft's sad death in a car crash in 2005 becomes even sadder when you realize that Disney supremo Wolfgang "Woolie" Reithermann, a mentor to some of the animators including Lasseter, died the exact same way 20 years prior (and just for good measure, former Disney studio chief and Renaissance alumni Jeffrey Katzenberg nearly died the same way as Ranft and Reithermann 10 years after Ranft's death and 30 years after Reithermann's, but he only broke his arm).
Pixar films' complete lack of female protagonists until Brave, coupled with John Lasseter at first dismissing the criticism as "We're a bunch of guys!" and Brenda Champan being fired midway through that movie's production, feel a lot more petty when you learn that, in addition to sexual misconduct, Lasseter's willful ignorance on the matter was the main reason women and minorities were regularly denied the opportunities to make such films (tellingly, Pixar's short films since his firing have featured more noticeably diverse leads).
Misblamed: Despite the creators making it clear that, as per their contract with Disney, they will only do sequels if they like the idea enough and not just for money, every one of their sequel announcements has been swiftly met with cries of "Sellout!". This was most egregiously the case with Cars 2, with John Lasseter green-lighting the sequel during the press release of the first film. They're also blamed (rightly or not) for the drop-off in traditional animation in American features.
True Art Is Angsty: Their realistic depictions of depression are one of the main reasons why most of their films are critically acclaimed.
Visual Effects of Awesome: Pixar is the company that proved that a feature-length CGI-animated movie could look beautiful in 1995, and they've only honed their craft since then.