Well Stannis is off the good guy list for sure but I don't agree it was out of character. They have been sitting it up for several weeks. It's all part of GRRM's power corrupts , what people will do to achieve it, and how others pay the cost theme.
- Stannis was shown as a man who loved his daughter but not enough to overcome his quest for power.
- When forced to chose he choose power rationalizing it by calling it his destiny and duty.
- When in fact it was the red priestess that manipulated him into it by spreading the fire Ramsey set.
I thought the scenes with him and his daughter and Davos and his daughter were great. You knew what was happening. The actual burning scene was the toughest to watch yet. It's all about the corruption of power and the cost.
Likewise I thought the Dani storyline was great. The CGI of the dragon was incredible. If you have a problem with the harpys not attacking in mass you must have a problem with every action movie made in the last fifty years. The hero's always fight them off one by one. They killed Hizdar because they viewed his as a trader for marrying Dani.
Finally getting a little payoff in the whole Drone plot. They are taking both Myrcella and the Prince back to Kings Landing which set's up an interesting season six. Overall still a disappointing part of the season.
Finally looks like Arya going to cross another name off his list next week.
Overall I thought it was a great episode. Certainly a shocker and uncomfortable in many ways but that's what GOT is. It pushes the limits in every way.
I'm going to disagree with some of your points.
You say they have been setting this up all season. I would say that they were doing just the opposite until 2 episodes ago, when Stannis and Mel had the conversation about burning Shireen. Even then, Stannis seemed to be totally opposed to the idea. HBO, made Stannis one of the most liked characters on the show when he had that heart touching moment where he tole Shireen how much he loved her and how proud of her he was. They have been developing Stannis as a just man who is inflexible, but who is doing things for the right reasons. Then they humanized him by allowing him to show that he has a heart. Then they did a 180 and turned him into a heartless power crazed *******.
What makes you think Melisandre spread the fires that Ramsay set? I didn't get that at all. My take was that she was in her tent staring into her fire and saw what was about to happen but was too late to warn anyone. She ran outside as Ramsay's 20 men were igniting fires in key parts of Stannis' camp. I felt she was just an observer. IMO, she doesn't have the power to make fire spring up yards away from where she is standing.
The actions of the Sons of the Harpy were really silly. Despite what you say about action movies in general, this was to an extreme. There must have been 200+ assassins against less than 15 defenders, and they were almost literally taking turns going on the attack. One more point. They can throw spears at Drogon, but can't throw spears at Mormont, Darrio, etc? What's up with that? Right before Drogon arrived, they had Dani's party completely surrounded and didn't even make a move. I would have liked for 1 of them to say something like, "lay down your weapons and you won't die today". That would have suggested that they wanted to take them all prisoner. However, HBO made it clear that they only wanted them dead, yet they all went about it like idiots.
As to Hizdar. The whole point of Dani marrying him was to get the Sons of H to stop killing her people. The Sons wanted the fighting pits re-opened and the Slave Masters to rise to power again. Hizdar was the top guy in one of the top slaving families and was finally in a position of power where he could make some changes along the lines of the goals of the Sons (as evidenced by the re-opening of the fighting pits). Assuming that they had been successful in killing Dani and her entourage, would they want to make enemies of one of the main slaving families in the city? HBO made it clear to us that Dani did not want to marry him, but had to in order to get the Sons to stand down. Then they had the Sons kill him. Seems illogical to me.
About Arya. Agree with your point. In HBO's world, Arya will only have 1 name left on her list. Cersei. In the books, she still has about 6 names at the end of book 5.