I liked this episode, although I admit there were problems, specifically that Daenerys’s transformation into the “mad queen” felt rushed — I get why it happened and I know that there have been references to the show going in this direction for a while, but I think there needed to be more buildup.
But I think, also, that I know what the main theme is now. It’s not so much that war is hell or power corrupts — although that’s a lot of it. It’s that vengeance corrupts. It’s self-destructive and self-defeating, something that the Hound made explicit last night. Cersei basically has run on vengeance, against Robert Baratheon for shaming and humiliating her, against Tyrion (who she thought killed Joffrey), against the Martells for killing her daughter, against the Sparrow and his followers. Daenerys’s quest also has been based in no small part upon vengeance against those who took the Iron Throne from her family — her final destruction here is also in large part about vengeance against those who killed her dragon, killed her advisor and friend, and won’t welcome her with open arms. For a few years now, I’ve seen a lot of comments about Arya turning into a soulless killing machine based on her quest for vengeance. And obviously, the Hound has turned himself inside out from vengeance.