They didn't put in the work to earn the ending they put on screen.I haven't had the urge to ever watch Game of thrones again. The last 2 season ruined it for me. I'm not mad at how it ended, I'm mad at how they executed it. I'm not getting into spoilers since there might be a few out there that haven't finished it, but Double D should've really taken HBO's offer of more episodes and even the additional season.
at last I will just wait for the books to finish up (if GRRM doesn't expire) to see it done correctly.
GRRM could end it exactly the same, but I guarantee he will earn it.