I've been reading this thread since I watched the episode last night but needed some time to mull it over before sharing my thoughts.
It was classic GoT in that it was shocking and brutal, I almost couldn't watch it (although I did, of course) and it was very uncomfortable viewing. Lots of satisfying scenes though, especially when the Mountain threw Qyburn and he went splat 
I agree with PPs that it's lost the depth and complexity that it used to have.
I think a lot of the theories on this thread are trying to make it more clever and complicated than it is now!
IMO Dany and Greyworm were always on the same page about avenging Missandei's death, but I don't think there was an explicit plan about how they would do it. It seems to me that Dany's rampage was a spur of the moment decision on her part and Greyworm followed suit, but I'm bitterly disappointed in her. Not a huge surprise though as they made it very clear she was going to go full tyrant.
I think it was absolutely stupid that Dany didn't use Jaime in some way. Couldn't they have taken him to the battle as a hostage and waved him in front of Cersei to try and make her surrender and then kill him in front of her anyway?
I loved the scene between Tyrion and Jaime but it was absolutely ridiculous that he was able to let him escape and get away with it.
I think it's right that Jaime went back to Cersei, it was romantic in a creepy way. Although it's ridiculous that he made it, especially as Euron was so sure that he'd injured him badly enough to kill him.
Now I really wish they hadn't gone the whole way with the Jaime/Brienne thing - it cheapens the mutual respect they had and doesn't do justice to her awesome character.
What will Arya do next? I don't think she'll kill Dany, she had her moment with the Night King.
I like the theory that Jon will kill the dragon, that would make sense as I'm sure he'd rather kill the dragon than Dany herself. She would be much less powerful without it.
I do hope Dany dies, she's always been annoying and she bloody well deserves it now.
Tyrion is an idiot, surely he used to be wiser than he has been in the last few episodes.
I'm not sure I care much about any of them any more! I suppose I like Sansa although she's kind of petulant and annoying.
Oh and I don't buy the love story between Jon and Dany (even before they found out they're related!) - just no chemistry and they're on different planets. It seems like he's being unfaithful to Ygrid even though she's dead.