(spoilers main) George has mentioned many times that he told D&D his ending, would they really make up all this stuff on their own?

I find it hard to believe that they kept the King Bran ending but made the rest of it up all on their own.

D&D must have known details about George's ending, he used to mention in interviews that they had long discussions about it.

I have no doubt they butchered the execution but a lot of the plot points have to have come from George, right?

It's also that George barely criticized the D&D ending while he was pretty vocal about criticizing HotD.

I feel that at the very least speculating about the future of the books based on stuff that happened in the show should be fair game.