...disappointed. Because Sanderson cannot deviate from the script too much.

But it seems he is portraying the last Forsaken at least slightly more sympathetically than any have been portrayed thus far.

It at least gets us to stop, and for one brief moment look at events from Demandred's point of view. The fact that we then immediately decide that he is still an evil mass murderer is not the point.

The point is the fact that he made us reflect on Demandred's motivations. Which means Demandred appears with a modicum more depth in our minds than he did before.

Well done Brandon. I'm certain that was inserted by you, and was not part of the original script.

EDIT

RJ had a similar opportunity with Lanfear, when he was asked whether it was the Dark One's touch that drove her to evil. He refuted this by saying that she was every bit as evil before the Dark One was freed as afterwards.

So nope, no internal conflict or depth of character there. That's not how RJ rolls.