Just finished the season, and I loved it. I agree that the first few episodes are a bit rocky - the split narrative between the camp kids, Jay/Lola, and Missy doesn't quite work, but I appreciate that they tried something different - but once 8th grade starts, everything kicks up a notch. I like that the more "concept" type episodes this season, "Nick Starr" and "Four Stories about Hand Stuff," wind up factoring into the ongoing plots of the rest of the season, and the resolution to Nick's storyline is great.
Some random things I loved:
Natalie's story about going through puberty/realizing she's trans - Gavin was the perfect choice to be a really terrifying Hormone Monster for her, and I like seeing how the hormone blockers protect her from him.
I was a little iffy about Milk at first, but by the end of the camp storyline, I love him (and his comments about his dad's friend Bob Reedy!)
Missy's arc is really good, although it feels weirdly self-contained - she has a few feature episodes that go in hard on her exploring her racial identity, and then she's barely in most of the other ones. Her bonding with Devon is nice, the code-switching song is great, I like seeing her with her cousins, and Ayo Edebiri does a fine job once she takes over the voicing duties - she doesn't sound exactly like Jenny Slate, but she still sounds very much like Missy.
The Anxiety Mosquitoes are yet another really apt puberty creature. I like seeing how the kids react to their anxiety in different ways. Nick freaks out and tries to run away from his (which leads to the Nick Starr persona where he cuts himself off from his emotions to "protect" himself,) while Jessi immediately starts nurturing/reinforcing hers and agreeing with everything it says about her, which is further encouraged by the Depression Kitty (I also like Connie trying to rescue Jessi from both of them but struggling to do so.)
Oh, Lola, never change: "That is cliterally my clitoris." The castle/Jayzilla imagery is too perfect.
Overall, I think they do a good job with Matthew's arc. I feel like his centric plots, when he gets them, are often a little more archetypal than the other kids, but the show manages to pivot them just enough to keep them from being too tropey. With his coming-out stuff, I like that he's scared, not just of his family disapproving, but of losing his close relationship with his mom and feeling like she's replacing him with his sister. The coming-out scene with his dad is really sweet. (Side note: how did I not know before this season that Aiden is voiced by Zachary Quinto?)
Andrew's crush on Michael Angelo - "Is that an accent I detect, or are you just British to see me?", ha!
The whole hand-stuff episode is great. Each vignette is both fun (Andrew's Bob-Fosse-style rundown of "the Glouberman method," I died!) and interesting, with good stuff to say, and I love the connective tissue of the hubbub over Devin and Devon's "divorce." I agree with whoever mentioned Devon clarifying that he's divorcing Devin because she's mean to him, that's a really nice moment. Also, I love Devin saying, "Please respect my privacy as I livestream for 12 hours and take questions from literally anyone."
Continuity references! I enjoy seeing Coach Steve's "bad mitten," hearing about the Ponytail Killer, and catching a glimpse of an autographed Fab Five picture in Jay's bedroom.
I like that this season puts a little more focus on the fact that Maury and Connie are both serving as Hormone Monsters for multiple kids. I like seeing Connie struggle in the fight between Nick and Jessi, "breaking up" with Nick out of her loyalty to Jessi but later showing up in her Beyonce Lemonade dress with the baseball bat to stick up for him. And I enjoy seeing how different Maury's relationships are with Andrew and Matthew, not to mention how supportive/protective he is of Matthew throughout the coming-out storyline - him yelling at Matthew's mom (even though she can't hear him!) is great.
The closing song is really nice. I was laughing the whole time, because I couldn't stop picturing Nick Kroll in the recording booth singing that song with his Rick voice, OMG.
I could hardly handle the "Poop Madness" episode, though. While I love the trippy Alice-in-Wonderland madness song, it's otherwise just too much grossness. Andrew' talking poop itself is bad enough, but then when you throw in the swollen bird carcass and Jay and Lola's disgusting pool, it's like there's nowhere to get away from it.
Also, is the hand-stuff episode the only time they mention that Michael Angelo is a 9th grader? He's drawn to look so much bigger/older than Jessi that a lot of their scenes together creep me out, because I kept wondering how old he's supposed to be.