I would say one of the key points is that Aang gets constant support from everyone around him. Like any individual, he’s nearly powerless without that support. Most other “chosen one” stories I’ve seen, the character is saving everyone else.

Sort of. Per TVTropes:

He deconstructs the Kid Hero. Each Avatar is supposed to learn of their identity at the age of sixteen, which is the age of maturity in the World of Avatar. However, when the leaders of the Air Nomads sensed that a war was brewing, they made the decision to reveal Aang as the Avatar four years early so he could finish mastering his airbending and start mastering the other three elements to nip the threat in the bud. This decision might have made things even worse for everybody involved at the time because it forced a huge responsibility onto Aang that the 12-year-old wasn't ready for, and alienated him from his pre-series friends who were themselves too young to know how to treat him post-revelation. After overhearing he was to be separated from Gyatso, his guardian and the only one left who treated Aang as the kid he was and as an actual person, he ran away, and then got trapped in a storm that forced the Avatar State to freeze Aang and Appa inside an iceberg for a hundred years in order to save both of their lives. He subsequently blamed himself for the genocide of his people and the subsequent century of war because he wasn't there, even after he's told he would've been too inexperienced to make a difference back then and that his running away then is probably the only reason there's hope for the surviving world now. His childish personality and cheerfulness is sometimes an act to try avoiding the burdens placed on him which proves to be a problem several times when he has to face a problem head on to solve it (like learning Earth-bending or spending almost the whole series avoiding the problem his morals might conflict with what he'll have to do to actually defeat the Big Bad).

They were going somewhere with the pacifism too, though ran out of time.

Korra straight up deconstructs it, which is more what I meant. She was born to fight, she basically never got to be a child/regular human, but being a 'Chosen One' doesn't fix anything. She's targeted and hated by the antagonists for being such a singular figure of authority, and beat up to a pulp over it.

I strongly recommend you watch it. It's very good.