So many people praised this show for being a heartwarming comedy that thrived because it relied on good performances of really great fleshed out characters. This season threw out all of that. Plot lines were introduced only to be forgotten two episodes later. Sometimes hitting play on the next episode felt like you had missed one because all the interesting and important stuff was left offscreen to be delivered in exposition. 
The biggest grievance I have with this season specifically is the decisions of how to treat and portray some of the characters. Nate's character arc was either forced do to a quicker ending than they planned or some fan backlash over his actions last season. Either way, it was incredibly unearned and felt so rushed. And don't get me started on whatever that relationship was. Rebecca went through the same storyline as season 1. In fact, most characters seemed to simply go through a final "aha" moment of their overall arc instead of developing any further. 
This show got so much credit for telling wholesome messages and it got a bit too much in its own head about it. After 2 seasons of no mention, it reveals that not one but two characters have been queer. While I would normally praise a show for inclusion, they both felt like forced diversity and played off one to be a trauma filled coming out (we have had more than enough at this point) and the other was simply a catalyst to thrust Keeley back toward our main love interests. The way that Keeley was treated this entire season was frustrating. She was finally starting to receive actual autonomy from the male characters when all of her storylines became cautionary tales and trauma. I know that plot doesn't have to be fair, but to see a character that has become a fan favorite and a good arc of positive change, to see her suffer in so many ways only to have her final moments be overshadowed by her relationships with men, seemed a bit cheap. 