I feel like this season had a lot of good ideas, but just didn't really have the time to execute any of them.
I feel like the pacing really dragged a lot in the middle, with not much happening. Which is a worrying sign, because this season is 10 episodes shorter than S1, but it still had worse pacing somehow.
Like, I didn't enjoy the 1671 Japan episodes in the beginning, because it was like 5-6 episodes in a row of Hiro just going on random adventures in the past with basically no moving plot. It becomes great once Kensei's betrayal happens, then it feels worthwhile, it's just getting there that sucks.
Peter is real fucking annoying this season, I'll be honest. He's just constantly clueless for 90% of it, and then just trusts Adam with his life. Like, can my man act normal for once? Let Peter be Peter.
I'm usually one to prefer shorter episode counts, but this show REALLY needs longer episode counts to work, because of how large the cast is. This season really screwed over a lot of characters and plotlines in terms of screen time for this reason.
Smaller characters from last season, like Janice and Nathan's wife (sorry I forgot her name) were pretty much written out of the whole show, with an offhand reference here or there.
Niki might've been screwed over the hardest this season. Not only is DL just flat out dead, but Niki herself lost all of her personalities (which, feels like a pretty dated and awful way to handle DID, but okay) but she also doesn't even appear for the first half of the season, it felt like. She also might be dead? Depending?
As for positives, I'm still really loving Claire and Noah. All of that stuff is still great, it was the peak of the season for me.
Hiro's stuff this time was also really great. His arc with dealing with his father's passing, and how he deals with Kensei is very satisfying.
Speaking of, I did enjoy Kensei as a villain. I think he's charming and has a unique background compared to everyone else. Wish he did more, which again, is another sacrifice for less episodes.
Small thing, but I love Nathan's hair this season. It's so wavy and pretty :)