*all spoilers below*
Given that this ending is being savaged over at IMDB and elsewhere, I might be the only viewer who actually liked it. Bear in mind that I was disappointed with the vilification of Dany in the previous episode and was determined to hate the ending.
Bran makes perfect sense as king. Not because he has any qualities of a ruler. He has none. Bran is so pre-occupied with visions of the past and future that he has no real connection to the present or anyone in it. Which is why he's cold. The council scenes toward the end suggest who will really be running the Six Kingdoms: Tyrion and the council. They will rule while Bran pre-occupies himself with visions and takes long away trips communing with the forest. I think the show runners are suggesting that this moment is a turning point for Westeros, from absolute rule of a single person to whose whim they are subjected to, to rule by a benevolent council with a monarch who is more of a figurehead.
Harking back to Samwell's suggestion of democracy, one which could only be met with laughter in that world because it was too radical an idea, I think what we saw there at the end is a transitional form. Rule by any council is a step up from rule by a single person, because the requirement of consensus tends to mitigate the disastrous consequences of rule by whim or even insanity of a single person. Rule by council consisting entirely of benevolent people who want to serve the people is even better.
John would obviously have been the logical choice to be king, but the show runners chose to make it politically impossible. They probably thought it was too gooey an ending for their modern sensibilities. It wasn't a crowd pleasing choice, obviously, because no one got to see the fairy tale ending of good queen Dany ruling with golden boy John at her side, or even one or the other. Instead they chose a modern theme of moving away from monarchy, a theme which I don't think the vast majority of viewers even realize. Most people are just like "Bran king WTF that makes no sense."
But given their chosen theme that is exactly why he was the perfect choice. I don't believe he had any ambition to be ruler. I think he came to be king because he foresaw that he would be king. He thinks everything is destiny, which is why he sees everyone being exactly where they're supposed to be and doing exactly what they should be doing.
So far as John's fate, I would point out that nothing is preventing him from leaving the frozen wastes and heading south. His brother is king of the Six Kingdoms and his sister is queen of the north. The unsullied were the only ones who would object but they left Westeros in the end. He may choose to stay in the wastes and form a new civilization there, or not. The point is his future is wide open.
Other character arcs were brought to appropriate conclusions. Aria in particular had a satisfying ending. She is a free spirit never wanting to be bound by obligation or convention. She should go and explore uncharted territory. It also sets up a premise for what could be a great spinoff series.
Bran lacks humanity. Well, literally. Cold indifference isn't a good quality for a leader. **cough cough**
I don't think this makes sense, but I understood the idea to remove the nature of born leaders--we crush Dany's wheel, but we are also left with Little Finger's ladder. They still have a system that will be infinitely corruptible and it probably wouldn't be long before some devious asshole gets the Lords of the realm primarily on their side and bribes their way into a new Kingship. ...obviously that can't happen until Bran is gone. Which is weird. What is the point of a ruler that knows everything all the time? How do you reasonably judge their decisions? ...is Bran basically immortal now? Is that kinda the point? With that, I kinda get it. You can't really take his position if he sees you coming, and can probably make a wise decision on selecting new councils and, in this way, lack of humanity means he has no interest in power. He doesn't want the role but he knows he is the only person for the role. He isn't going to be consumed by power because outside of Drogon, I guess, he's the most powerful thing in Westeros. It looks like he plans to find that dragon and bring it back to King's landing or at least establish a proper detente.
Anyway, I don't really mind how things ended with where people went, but it was about 3 necessary episodes of material crammed into this episode. Jon taking care of Dany, increased drama with Tyrion in prison, other messes being cleaned up, should have been one episode. Dealing with succession and the new leadership model, another episode. Even a few rebellious lords here and there threatening their power, a bit more threat from the unsullied and the dothraki (both of whom seem to have respawned again?). Bran and Drogon, a bit more development of that whole 3 eyed raven thing, maybe the White Walkers and Children of the Forest, and of course Jon and his wildlings.
Instead, we got a 1980s montage of stealing the jock's Ferrari, chopping off the engine, sticking it on your shitty boat, and winning the island's annual yacht race in a span of 15 minutes.