> "What were the writers thinking?"

As for the Game of Thrones -- that's exactly what JRRM envisioned. At some point he sat together with GoT storywriters and producers and laid off all the plans, how who dies, and of course the finale.

I think the finale was awesome -- what a nice populist autocratic ruler may become. That sometimes life is not what you want it to be, and you cannot change it. That your favorite characters don't always win.

PS: I only regret they pictured protagonist Tyrion (the dwarf) somewhat nice. The whole GMMR's idea was that his character was repulsive, incredibly ugly, but did good things all the way. That would stand off from pretty much all the movies, when I can tell who's who from the first minute (good are cute, bad are ugly).