Well, not as bad as Rob Bricken at io9.com thinks.
But then, Rob's anger at the season finale comes from a guy who is pretty invested in the show. Me, I was always lukewarm at best (check out my first post about it), but then my ears pricked up as the last few episodes (specifically the season's penultimate episode, "Past Is Prologue") seemed to be getting tighter, more rational, with the characters behaving in their own interests, instead of the plot's interest. But the finale let some of the air out of my slowly inflating interest balloon.
Some of the things that stood out in a bad way (instead of "stood out" maybe "sat down"):
1. The Rosewater sisters. I'm sorry, but they're just useless. Not the fault of Julie Benz and Mia Kirshner, the actresses; it's the writers. Maybe I missed it, but I never saw Mayor Amanda do much of anything besides make flat-footed speeches and say "that's wrong"; and the idea of a madame/hooker who falls in love almost immediately for the tough hero of the show is just so tin-eared that you want to reach through the screen, past the show itself to the writers room, grab O'Bannon, Murphy and Taylor by the collars and yell "Talk to a hooker! Just one, for research! God knows, you're all LA writers, you've certainly used them before."
2. Doc Yewll. She's a former mass murderer, smarter than most every other character, a techno-savvy cyborg with the skills and ability to kill - and she sounds like a tough dame from a 1940s gangster movie! (Way to go, Trenna Keating.) But she doesn't see the Earth Republic goons coming and gets taken hostage like a UN observer in Somalia. You'd have expected her at least to booby-trap her lab.
3. When Nolan and Irisa break out of the Earth Republic lab, it was every first-person-shooter visual cliché you've ever seen.
4. I'm sorry to say it, but the little kid they found to play Irzu has a thousand watts more charisma than Stephanie Leonidas, who plays Irisa. She stole the scene from Stephanie in less than 60 seconds. Maybe it was the fact that she sometimes smiled.
5. Why, why did Kenya Rosewater warn Stahma about what she was going to do? Really, kid? Give advance notice to your potential victim? How did you survive to own your own bordello in the first place?
So here's the thing...notice how most of these gripes have to do with female characters? And how the show runners are guys? Sigh. (I will admit that the most interesting character on the show is Stahma, Datak's wife. They got her and Datak right. And Nicky Riordan was fun as portrayed by Fionnula Flanagan, but she's dead now.)
However, unlike Rob, I *did* like the way that Datak finally loses control and sabotages himself. (I won't say how...spoilers). I thought it was perfectly in character; if there weren't the potential for Datak to do something like that, he wouldn't be nearly as scary as he is; it's necessary to make him unpredictable.
Maybe the real problem is that the writers are only comfortable with Nolan, Stahma and Datak as characters who actively drive the story forward; the rest feel too often like set dressing.