This isn't just a case of a show not living up to the hype. There are profound failures of narrative, characterization, pacing and story structure occurring. Things that simply didn't exist when the show was adapting the books.
It's easy to say "You built it up too much in your head" or "It isn't playing out like you wanted it to" to try an explain the negative reactions, but the truth is this season has been messy, slapdash, and often incomprehensible. Characters who were once brilliant are now morons. Plot threads that were built over seven seasons have been thrown out as quickly as possible in a race to get to the finish line. It's just been a mess. That isn't my expectations or what I built up in my head. That's objectively looking at what season 8 is doing and saying "This is all just off. Badly so." That Starbucks cup on set making it to air is, in some ways, indicative of how all this feels. Rushed, unpolished, and sloppy.
Dani's heel turn is a prime example of the issues facing the show this year. Sure, there was some minimal groundwork laid for the idea she could go bad. It didn't come out nowhere in terms of concept. But it may as well have come out of nowhere in terms of execution because the show has done almost nothing to earn what happened last week. She was a character who had, on occasion, displayed some authoritarian tendencies and seemed to have some issues with arrogance and wrath. But it was slow burn stuff. If you want to make a character break bad over that, you've got to a better job than just say "Oh, this secondary character pal of hers got murdered, she's crazy now and just killed countless innocent people in a horrific firestorm because of it." That's bad writing. Everyday of the week.