I kinda expected from the books for Dany to turn evil, or at least morally neutral, as Martin rarely writes pure good or evil characters (except Euron and Ramsay in later books), but the show simplified her and it seemed she'd turn out good then they had to do their ''subverted expectations''.
This is a minor problem, and the battle was way one-sided, but what about all other ruined characters, it's much worse with them, it started with Stannis, then Dorne, Arya's training was pathetic, Varys, Littlefinger, and Tyrion lost their intelligence which imo was the most interesting part of the show/books, Bran became boring which is quite an achievement for the most magical person in the world, Euron became a joke of a villain, not as intimidating as in the books, except when he had ballistae that could sink the Yamato. Jaime, in the end what's the point of him, what's the point of the Iron Bank, they've build up the Night King threat who doesn't even exist in the books, what for, etc. in the end most things don't make sense, the Dothraki and Unsullied resurrect themselves and King's Landing repairs itself when it's convenient. I liked the Clegane fight, and the build up to the battle of Winterfell, that's it.
The Faceless God is one of many avatars/masks of Nyarlathotep, it's very similar to the Many-Faced God the Faceless Men worship. I don't think they have a mortal boss, the Kindly Man or Jaqen, they are all ''no one''.
The World of Ice and Fire book added a lot of Lovecraftian places and stories to Essos.
only part that seems similar to Vance's books is when casters forget spells and need to memorize them again and again, I don't remember nothing about alignment, or any developed magical system