I'm actually on the other side and I appreciated the episode (not perfect, but I appreciated it), and here are my opinions:
Ups:
+Top notch acting from Peter Dinklage, Nikolaj Coster-Waldau, Lena Headey, and Emilia Clark. Emilia plays her character's struggle from madness really well.
+Daenerys' arc. A lot of people may dislike it, but it's better than just taking the throne and cleanly defeating Cersei. It's in her DNA and we've seen tendencies from her madness in the previous seasons: coldy watching his brother die, burning people who refuse to follow her. She has constantly struggled to keep it but bad things keep on happening to her. She lost two of her dragons, her most loyal friends, Tyrion keeps on failing her, and Varys and Jon had betrayed her. Then she just lost control. Cersei is the evil queen, while Daenerys is the mad queen.
+Cleganebowl. People complained that its too "fanservice", but if it didn't happen, people would have complained the other way. Almost everyone has been waiting for this! Let's just appreciate that it was beautifully choreographed. It had the elements of Hound vs Brienne brawling. I loved the callback from Oberyn when Gregor attempted to crush Sandor's eyes. Luckily, Sandor was on guard here so he barely survived it. While I really wanted Sandor to win, a draw is a good way of both men going down looking strong.
+All of Jaime's scenes. His scene with Tyrion really melted my heart. Well done by both actors. I weirdly liked his battle with Euron as it finished his arc of left-hand training by defeating a crafty warrior in Euron. As for his scene with Cersei, while I wanted him to kill Cersei, their final moment was quite touching, enhanced by Lena's and Nikolaj's acting.
+Arya deciding not to kill Cersei is quite a character development. It gives her more vision in life than revenge. This allowed her to be more sympathetic to the sack victims.
+ I like how this episode has gave me an idea on how the Tywin's sack of King's Landing looked like.
+Qyburn's death lol. As cunning as he is, he's still just a villain's sidekick so him getting a somewhat comical death is good for a chuckle.
+Cersei doesn't surrender. She has never surrendered. Not to the High Sparrow, not to the Dragon Queen.
Downs:
-Varys' death. Mixed feelings here. I liked how Dany delivered her promise back in season 7, but Varys shouldn't have died. I already disliked how his role has diminished since season 6. He's a smart person, smarter than Tyrion. Though Tyrion (closest thing he has for a best friend) betraying him at least didn't make him a complete fool.
-Arya's plot armor. So thick! She keeps on surviving. The same somewhat applies to Tyrion.
-The Golden Company looking like asses. Cersei bought them with Highgarden gold! They didn't deliver the elephants. They didn't deliver in battle either.
-Jon Snow being blindly loyal to Daenerys. The honorable Jon Snow took about 3/4 of the episode before helping the victims of the sack.
-A bit rushed. I still feel a 10-episode format would have benefitted this season.