There isn't even a Night King in the books (there's an unnamed God of darkness whom the Others apparently serve). Given that he used to be a man before the Children transformed him, but he wants to destroy men, I don't think he has particular complex motivations. The bottom line is that his character isn't well thought out and his whole purpose in the story was to be a Deus Ex Machina solution for the good guys.calumnus said:
I was less happy that we did not learn more about what the Night King wanted, and now it seems like the battle with Cersei will be anticlimactic. The Night King and his zombie army was scary. Cersei is not scary. She isn't even that evil.
I was also not happy that the living split their forces, sending the Dothraki out into the night (if you are going to attack the White Walkers, why not attack them in the day?). Defend the castle, then maybe attack with the Dothraki from the flank? Why be so stupid? The Unsullied were just thrown to the wolves.
I would have rather the Night King overrun the North with key main characters escaping, then the Night King advancing on Kings Landing, destroying the Lannister army, with Arya only taking out the Night King at the end.
As for military strategy, it must be said again that Jon is the all time worst military strategist.