What I miss are the monologues. Mon Mothma's rebellion speech in the Senate needed to be on a par with Maarva's "wake up" speech or Luthen's "I burn my decency" speech, but it just wasn't at that level, and in the end they had to recycle Nemik to be the voice of the rebellion.
The writers were forced to treat the Rebels cartoon as canon. You should hear their quotes about the quality of the writing in "Rebels". Totally justified, but it's what we got.
There was some really sharp writing where the Deedra and Syril relationship was being held up as parallel to the Cassian and Bix relationship, and where Luthen's struggles and the ISB struggles were shown as the same, but they never really got the payoff on that.
I don't think in the second season that they really knew what story they were telling. I described the first season as, "This is the story of how someone who you wouldn't even want as a friend, became the sort of man whom when he asks you to go on a suicide mission with him, you do just because he's the one that asked you to." And they really didn't dig harder into Cassian's arc or really even seem to understand that was the core story they were telling. Melchi just had to stand in for that as the whole of the Rouge team, but I'd rather they pared down stories they weren't taking anywhere and given us more of Cassian building trust with the other "Rogues".
I likewise feel every secondary character was wasted. Mon Motha was never really shown as awesome. She ends up looking like a figurehead not prepared for her role as leader. Mon Mothma's husband got far too much screenplay to end up just as a playboy in the end. If a character gets screenplay, it should be because they change over the course of events, and really, I felt the husband deserved to prove he had been wanting to be her faithful spouse all along by dying to help her escape the Senate and that the tragedy was the two people who loved each other but never understood each other. Mon Mothma's daughter got way too much screenplay to just disappear. Brasso was way too important to the story to die a meaningless and totally out of character death purely for the shock value. Brasso is way too cool of a customer to just panic under pressure with no motive. Saw Guerra never had any story arc and ended up being just fan service. Luthen ended up being weak and pitiful, which is not what I think the audience wanted to see. Cyril being conflicted wasn't a surprise but just going out to die and not getting his own monologue before Cassian says, "Who are you?" is a waste of how much time they spent developing his character. Deedra going down hard isn't a surprise, but Luthen not even trying to save Lonnie or not even having a plan for it was a very disappointing mark on his character. That Luthen has become too much like what he hates is something we knew, but that he wasn't fighting against it was not how the character should go down. Honestly, what's B2EMO doing in the show at all except looking cute?
The Ghorman Massacre was OK, but it felt like the same scale as Ferrix and it should have felt more like the scale of Tiananmen Square. So much of the second season felt like, "We just don't have the budget to tell the story we want to tell."
It's still for all my complaining the best thing Disney has done that isn't Rogue One or the first season of Andor, but it's also not so good I'm going to watch it again and again like Rogue One or another good Star Wars movie.