I think people are being a bit harsh. It's impossible to bring an emotionally satisfying end to a series like that in a believable way, because world's don't end. The only realistic way to do it is to simply stop filming without most things being resolved, because that is how life is. Most people would be pissed at that, as they were with Sopranos and that was a far simply world. The other alternative would be to just kill off everyone, so all their stories really do "end". People would have been pissed about that too.
Instead, they tried to answer most of the major questions while allowing that theoretical world to continue and without an obvious cliffhanger that would have also pissed people off.
I mean, if Daenerys hadn't wiped out the city, then the last two episodes would be rather boring, and counter to her proven vengeful nature. So, she had to do that and therefore Jon had to kill her, otherwise it would have ended with her about to set off to destroy/liberate the world. And if Jon kills her, then we can't have him killed by the unsullied, or it would have ended with a cliffhanger of the Unsullied and the armies of the North poised on mutual destruction.
Although Bran's character was annoyingly disappointing and not very useful during the battle with the whitewalkers, his choice as King made a lot of sense, including in the minds of that "council" . He was knowledgeable and benevolent, had no enemies, and the fact that he couldn't have kids I thought was a clever way to convey the "breaking of the wheel" and end to rule by birth into a particular family. His "lameness" both physically and personality-wise made him a good choice as king.
Arya, the most likable character throughout the series IMO, makes the most sense as a spinoff, and her ending set that up. While her or Sansa beheading Cersei would have been emotionally satisfying that would have been too unrealistically "neat". I thought robbing the audience of that kind of vengeful bloodlust against someone so vile and having her death be incidental and at no one's direct hand was amusingly realistic to how most evil fucks die.
Dragon melting the chair was hit-over-the-head "symbolic" but not as silly as people make it out. It's been made it clear that the Dragon's are extremely intelligent and highly attuned to Daenerys thoughts and feelings. For the same reason, Dragon knew she had been stabbed, he'd know what the throne was and represented, and want to destroy it as she would have if she couldn't have it.
My biggest problem with the episode was how did anyone find out that Jon stabbed Daenerys in the heart? No one was there and Dragon flew off with her. That implies Jon admitted to it which was selfishly moronic. The whole point in killing her was to prevent further war and bloodshed. Admitting to killing her made war with the Unsullied likely. While they would have suspected him, he could have made something up like an assassin ambushed her in the throne room, Dragon came and incinerated him then flew off with her body. OTOH, Jon is the kind of Putz who would admit to it out of honor.
Others have complained that the Unsullied held Jon prisoner rather than kill him immediately. But the Unsullied don't make their own decisions. They were slaves their whole lives and then willful servants to Daenerys who mindlessly followed her orders. So, it makes sense they would not act on their own.