I agree... this short story has quite a powerful impact. I wish my words were as well-chosen and efficient as yours. ^_^
And I do wonder how the creators will write themselves out of the hole of having Aang be the last airbender. They will either have to leave the cycle broken, as you have done, or write in a surprise airbender somewhere.
I hope it is left broken. The story is more meaningful if the world eventually has to learn to balance itself and quit relying on the Avatar.
But now I'm just rambling.
Thanks for the excellent read!