The wrap up to Game of Thrones proves Hollywood has become too addicted to the twist ending.
Lots of great shows, and great stories succeed because they have a surprise twist at the end that is really clever and subverts expectations. Even when an ending is foreseen, a really great writer will work the story out so that the average reader can't see how the heroes will win in the end, until they do. Hell, Rod Serling, proved he was a master of the twist ending fifty years ago with "The Twilight Zone," and done well, the twist ending is an absolutely great literary device. But it's not the answer to everything. You never want a story to be predictable, but a story doesn't have to have a twist ending to work.
The Game of Thrones, as a series, is a story that fails, in that regard. I think it fails because the writers are trying too hard to subvert our expectations. The expectation is that Dany, after 7 seasons as the protagonist, is expected to win. Another expectation is that, although Jon Snow is actually the legitimate Targaryen heir, with the best claim to the throne, he falls in love with Dany, and supports her. So the expectation is that Dany wins the Iron Throne, or that perhaps the two of them end up sitting on it jointly. But Weiss and Benioff don't want to do what viewers expect, so here we are.
This is a mistake.
Think about it: in the greatest of all fantasy epics -- The Lord of the Rings -- everyone really knows, right from the beginning, that good will triumph, evil will be vanquished, and the good guys. I doubt any reader who ever cracked the book expected Sauron to win, in the end, so the ending is very far from a twist ending. Same with the Harry Potter series. Voldemort was, we all knew, destined to be vanquished. Ditto Star Wars, where we always knew the Rebels were destined to win. We know that the victory won't be permanent victory, because that's not in the cards for human beings in the real world, imperfect as it is. But the cause of right and justice will be advanced. There's really no twist. It ends like we expect it to. The only question is, how will the author manage it. Tolkien managed it quite well. Rowling did too, and so did George Lucas.
But Weiss and Benioff haven't. They haven't even tried to make the expected ending work. Instead they've gone with a rather predictable route, that Dany goes full mad queen, and becomes the monster. The problem is that it turns off audiences because it's just wrong. She's shown signs up to now of being a little too ruthless from time to time, but still she's always basically been someone with a good moral center, and especially, with her determination to free the slaves of Mereen, someone with too much empathy for the weak and helpless to suddenly become a genocidal psychopath.
Also, twist endings work better for short stories. For grand, unfolding epics, I don't think it works. Over the course of eight seasons, people invest too much hope and affection in a character. And when you take a beloved character and flip the switch at the last moment to make them the villain instead of the hero, people will HATE it. It also seems lazy. In their desire to provide an unexpected ending, they've gotten lazy and just flipped the switch on the main protagonist's character, and it's not that believable to most people, who get it that nobody that evil just turns that way overnight.
It looks like Game of Thrones will join the reimagined Battlestar Galactica as a great series, with a massive letdown of an ending.