Through 7 seasons they never really developed the Night King. The only way you can understand the motivation of a character is through dialogue. You never get that with the Night King. He was created by the Children of the Forest (was it part of their war against men?) As I recall, didn't they regret creating him and the white walkers? So I don't know what you could have expected in the scene with Bran. I have not read the books so I'm just going with what I remember from earlier episodes. With the other characters there has been dialogue and intrigue. With the Night King all we've gotten to create any "drama or tension" is "Winter is coming."