My wild guesses.
Too many dragon skulls in the catacombs at King's landing.
They all die before it's over.
As will Jon, Dany, Sansa, Jamie and Cersei.
Littlefinger and Varis both survive because that's what they do.
I think Arya wins the game.
In Seven Samurai and Magnificent Seven only 3 make it.
I expect similar numbers…