As cool as the Night King and White Walkers were, they were basic one-dimensional villains who were just evil for the sake of being evil. Even in the main show/books, I always found the Lannisters and Daenerys' lust for power to be the more intriguing issue that had to be dealt with. Their motives were (somewhat) understandable.
I don't think the WW in the books are going to be just one dimensional evil zombies, There's clearly more to them than just that; first, their name is much more descriptive of the trope of
The Others, which is a group of people
otherized by the narration and the point of view of another people. Something typical in the wars that GRRM hates so much.
Lost did the same with their Others, presenting a group of people who were already in the Island as some group of evil villains, but that as the story progressed, they actually had more of a grey moral and justifications for their actions. They were good people in the beginning that just become corrupted for a series of events that happened to them.
It's literally the same as the wildlings and how one group hates each other and sees the other side as evil just by their positions at one side or the other of the Wall.
I don't think the Others are going to be more evil than Tywin.
