Maybe I'm the only one, but honestly I was a little disappointed that it wasn't Jon that killed the Night King. I understand the idea that the show wanted to buck conventions by not making it the conventional hero who did it but not doing something just because its conventional doesn't actually make it a good decision. Jon was the one who confronted the white walkers first, he'd fought white walkers before, he had that stare down with the night king after Hard Home. It felt like that final confrontation was the end to his narrative ark, and then he didn't get it. Meanwhile Arya had almost no connection to that particular plot thread, I just didn't like that decision.
Its would be like all of star wars laying out the way it did, but then Luke gets lost in the death star on the way to confront Vader and Leia jumps out of a shadow to stab him last minute. That would also buck convention, it just wouldn't make any sense given the plot of the story.