“When we hit our lowest point, we are open to the greatest change.”
What irks me about this moment isn’t that Aang is being rather OOC in giving Korra what she wants rather than allowing her to develop from her loss of bending, but rather that in the context of his actions this line plain doesn’t make sense.
Aang is not changing anything by giving Korra her bending back; he’s simply putting things back to the way they previously were. Giving her the ability to energybend is not changing anything either, as it’s only giving her the power to rewind events like he can. Giving her bending back so quickly is not changing anything, just enforcing Korra’s viewpoint that bending is all she is and that being a bender is inherently superior to being a non-bender.
This line would have made perfect sense had Aang given Korra time to live life as a non-bender, allowing her a chance to see life from their viewpoint and to learn that her entire being is not only centered around her bending like she believes it to be. She would ‘change’ from a stubborn bending prodigy after she had hit her ‘lowest point’ into the Avatar who is compassionate to all people, benders and non-benders alike.
Instead he hands her back what she lost under the guise that he is allowing her to grow into the Avatar now that she’s finally been able to communicate with him. She doesn’t learn anything from her brief period of being solely an airbender, instead only having to cry about it before she’s handed her other bending skills back. The entire twist of Amon taking her bending is rendered moot, and the only thing she gains from the experience is a convenient way to tie up the plot point of people losing their bending to Amon.
Not only that, but it teaches us that Tenzin’s teachings were wrong because in the end it wasn’t patience that Korra needed to get in touch with her airbending and her spiritual side, it was simply mortal peril and depression respectively.