I smiled and laughed and yelped and waved my arms around! Korra & Asami Did The Thing!
And then in the comments on io9 I found a link to zuko is my sugar daddy saying, “people saying that korrasami had no build up and was forced …” followed by 48 images of Korra and Asami over four years of Avatar: The Legend of Korra which leave no other possibility for what happened in the final episode. This is how good short-form animation can be.