Yes, he sent ravens. I am not particularly enthused about that plotline, after how the handled even the NK and the WW
Imo it doesn't matter what Bran does. At this point i think most people are let down that the obvious climax was more trope-ridden than anything else in the show.
Though you can be sure that some fun-bois will even consider this as ok if there is even some allusion to the NK being reborn somehow, or WW etc by the end of this series. I personally doubt that even that will happen, but why not? No serious plotlines here.
People die just when the directors have to check the box 'x dies here', with no logic and plenty of ex machinas save others (or prolong deaths, as in Jorah). Theon's death was stupid, imo. Of course he wanted to fight for Winterfell, yet much like some others he apparently becomes a super-fighter by the end. This looked more like Legolas and Gimly than season 1-4 Game of Thrones
Re Arya, yes it would still have been workable for her to kill the NK (imo the NK shouldn't even die), but as others noted Not in this braindead way. It would have been better even to have her just sneak up to him and kill him instantly. That he stopped her, then acted like another dumb zombie or human, was even worse imo.
Dynamics are very problematic: if a side kills the WW, why would anyone bother with what happens with Cercei? She could even win (i doubt it; probably Yara will be the ex machina in that episode
) and it doesn't mean anything imo.