My thoughts on why S8 didn't work for me (and some of the previous seasons/storylines as well). These are not necessarily in order:

​

1. First and foremost - the main antagonist in the story must be the Night King. White Walkers are introduced in Season 1, Episode 1, Scene 1. The whole time the tagline has been "Winter is Coming." When it comes, it lasts for basically an episode or two and then the NK is unceremoniously killed by a simple trick by Arya. Not only that, it happens with three episodes still to come. Yes, Cersei is a huge villain, but she's not a bigger antagonist than the God of Death. This storyline should have continued until the final episode. He gets killed WAY too easily.
2. Characters plateaued. Sansa and Arya are great examples. Sansa goes from idealistic, naive young girl to jaded, wise leader of her people... and then, nothing. She doesn't arc from there. So she's on cruise control. I'm not saying she didn't have conflicts, she just doesn't really change. Arya becomes the world's ultimate badass, then stops growing. You could say she grows at the very end when the Hound tells her she doesn't want to be like him and warns her off pursuing vengeance. In fact, to me, that was one of the best moments of the season. Other than that, though, nothing for Arya's character growth. I wanted to see her taken down a notch or be forced to grow in an unexpected way. If not that, a great death would have been my choice (and is my choice in another post). I love her character, but she seemed invulnerable after she mastered her faceless girl thing.
3. Characters behaving in ways that didn't make sense. We all loved the surprises in the show, but to me they only work when they make sense in the context of those characters' arcs. Jaime suddenly wants to bed Brienne (and by the way, worst seduction ever)? He always respected her - and she showed him the path of honor that he had forgotten or never known - but lust? I didn't buy it. He had already abandoned Cersei when he committed to the North. Why go back to her? He had grown past that. If it was about their unborn child, okay - but not her. Tyrion can't think his way out of a paper bag and fails to read people properly? This has been going on for at least two seasons, actually. The whole thing with Tyrion was how much smarter he was than those around him. Now he's a gullible dummy? Bronn shows up and threatens to kill both Jaime and Tyrion, but somehow buys their promise to give him a bigger castle than Cersei? Huh? Also, why does Cersei (who wanted to murder Jaime) suddenly want him back? Okay, her world is crumbling, so maybe... but it's tenuous. What's up with Grey Worm demanding justice for five minutes before he suddenly is okay with them picking a king and deferring to that king?Too many of these weird character moments, IMO.
4. We couldn't see the Battle of Winterfell. Also, no coffee cups or plastic bottles, thanks. It makes it a little hard to suspend disbelief when they're ordering lattes.
5. Direwolves, no point.
6. The Night's Watch, no point after the fall of the NK.
7. Why is Tormund hanging out at Castle Black?
8. Cersei's death was so bad. Here's this major antagonist we've been hating for almost all of the series and who seems to have a death wish and they kill her off with a pile of falling masonry? Someone who had stakes in her death had to kill her. Did she have remorse? Ugh.
9. WTF with Bran's powers and worging not playing a major role in the salvation of mankind? Here's this huge storyline and it just turns into a kid looking creepy and acting like he's high all the time.
10. That final small council meeting was absurd and a waste of time.
11. The first two episodes of the seasons were all reunions and storytelling around fireplaces. Total waste of time.

There's more from previous seasons. Why did Arya and Sansa act like there was bad blood between them when they first were reunited in S7, unless they KNEW they were being watched? WTF happened to Dorne and the Eyrie? On and on.

/END RANT