-Jon initially rejecting Cersei's proposal was bizarre, to say the least. At first, he says that the "great war is here". The essential message is that houses, allegiances, and disputes over who should rule are all irrelevant in the Great War to come. Yet Jon, somewhat hypocritically, values his allegiance to Dany (again, how he was convinced to bend the knee is unclear) as his queen more than he does compromising with Cersei. He's embroiling himself in the political game when his principle goal throughout the past several seasons was defending the realm from the White Walkers and protecting the North.
This artificial scene was forced in by D&D to solidify the artificial Jon+Dany relationship.
-Winterfell was a mess. Conveniently, Bran just happens to tell Sansa now and both Sansa and Arya just happen to catch onto Littlefinger's ploy now (their animosity towards each other in the previous episode seemed genuine). As D&D described in the "Inside the Episode" video on YouTube, the goal with Winterfell this season was to create this Sansa/Arya conflict and give viewers the impression that one of them would kill the other, and then surprise the viewers at the end when they kill Littlefinger together. It just didn't work. It seemed entirely forced. The motivations and actions of all four characters in Winterfell (Bran, Sansa, Arya and Littlefinger) were entirely unclear. There was also significant inconsistency. In the previous episode, Littlefinger suggested that Brienne could mediate the conflict between Arya and Sansa. But if he wanted Sansa to kill Arya, which is what he seemed to want this episode, why would he say that? Why didn't he tell Sansa that she ought to deal with Arya last episode?
-D&D are quite averse to killing major characters. The only "major" characters killed this season were Olenna and Littlefinger. Neither of them were really top-tier characters, though. Sansa, Arya, Jaimie, Cersei and Tyrion were left unscathed this season even though none of them are absolutely necessary at this point in the story.
Cersei could have killed either Tyrion or Jaimie this episode, and yet she didn't. There's little suspense when we know that the main characters aren't going to be harmed.
-I must say that Viserion's blue flames are absolutely stunning. Props to the CGI team. However, when Viserion was struck by the NK's spear, it seemed as though his "fire-tank" was destroyed. Admittedly, I'm not an expert on wight-dragon biology.
-The whole annulment thing seems far to convenient. It's unfortunate if that's what happens in the books. And how Gilly just randomly happens to read out loud that piece of information to Sam is also pretty convenient.
-The Theon scene was excellent. Theon is one of the most interesting and morally ambiguous characters in the show, along with Jaimie. He has struggled with his identity his entire life. I'm glad that he's finally made the right choice.