I love ATLA. It's one of my favourite cartoons, even as an adult. It's an overall solid series.
That doesn't mean that it's a flawless masterpiece. It has plenty of flaws, and is a product of its time.
Plenty of people have talked about how Kata/aang turns Katara into A/ang's prize for saving the world, how one sided it is till the eleventh hour and so on. What I want to focus on is that it also just doesn't work from a structural storytelling standpoint.
In screenwriting there is something called "Want Versus Need." The general idea is that a character starts out thinking one thing will fulfill them to realize that something else does the trick instead.
Take Dipper Pines. He "wants" to grow up fast and be taken seriously by the adults and teens around him, being seen as an intellectual equal. What he actually "needs" is to enjoy his youth while he still can and realize that his bond with his twin sister, Mabel, matters more than trying to grow up too quickly.
His crush on Wendy is really just one part of that larger "want." Wendy is 15, and is a few years older than him. Part of the reason I think this, beyond the usual pre-teen hormones and being infatuated with the idealized version of her he's built up in his head, is that he probably subconsciously believes that dating her would make the older teens in town take him more seriously. While the show never says this outright, I wouldn't be surprised if that's what's going on given the rest of his character.
At the start of season 2, Wendy talks with him in private and turns him down. Dipper accepts this. They go back to being friends.
This is fantastic character writing. That romantic subplot adds to Dipper's overall character arc rather than derail it. By giving up his crush on Wendy, he is forgoing his "want," which makes him grow as a character. This also gives the series a stronger thematic throughline.
Plus, it's realistic. A teenager won't fall for someone that young due to the huge maturity gap. Wendy turning him down checks out.
What the fuck does that have to do with anything? ATLA does the opposite with its main character.
If I had to guess what A/ang's "Want" and "Need", they would be…
Want: To be an ordinary kid and enjoy childhood.
Need: To mature without losing his compassion, accept his responsibilities as the Avatar and restore balance to the world.
Which is a bit cliche, I admit, but it works as a character arc. You don't have to reinvent the wheel for those, after all.
Part of his "want," like with Dipper Pines, is his crush on Katara. It showcases another example of his desire to cling to childhood.
After he's freed from the iceberg by Katara, he decides on the spot that she's his soulmate that he will ride off on penguin sleds into the sunset together with based only on the fact that he likes her. That's an extremely childish view of romance. Your first crush is rarely, if ever, the one you are meant to spend the rest of your life with. It takes years of trial and error to find that person, if at all.
It also makes sense why A/ang sees relationships this way. He was raised by monks in an Air Temple rather than by two parents. There's nothing wrong with that. Unconventional family structures are just as valid as traditional ones. The issue is that the Air Temples were segregated by gender, so he never really had the chance to interact with girls his own age or develop a realistic understanding of romantic relationships.
Plus, he's twelve. It's pretty common for people to have unattainable crushes at that age. A/ang's no different. The fact that Katara is highly likely the first girl his age he ever saw in his life adds to this even more.
A/ang isn't a bad person for this. He's still a good kid. It's just the narrative adding something that he needs to outgrow.
If I was watching this series for the first time, I would be under the impression that the series has a similar set up to Gravity Falls. You know, have A/ang let go off his childish crush at some point and move on? It would play into his large character arc of letting go off childish things that are holding him back and grow up, including his crush on Katara. His arc is an inverse of Dipper Pines, after all. It would've served as a fantastic lesson for the young boys in the audience, being a demonstration of how to handle similar situations in a healthy manner.
That never happens. When A/ang is confronted by the garu and says that he must let go of his crush on Katara to attachieve the Avatar State, the series gives him an off ramp where he gets to keep his obsessive crush and achieve the Avatar State without sacrificing anything. This should emotionally stunt his character due to not learning anything and getting exactly what he wants, but it has no consequences.
This is straight up bad writing. It undermines the character arc the series spent a while building. Instead of resolving the conflict through Aang's growth, the story changes the rules so he never has to make the sacrifice it told us was necessary.
The romance also actively weakens the story's structure. Rather than forcing Aang to outgrow his childish view of love, it validates it and rewards him for never changing.
The better decision would have been for Aang to be unable to achieve the Avatar State until he finally let go of his crush and moved on. This would force him to confront the fact that growing up means accepting that not every desire can be fulfilled, even if those feelings are genuine.
Plus, A/ang's a kid. He doesn't need a love interest at the end of the series. If the writers wanted to explore his romantic life later, that could have been done in Korra. But during the original series, his story should have ended with him growing as a person, not "getting the girl."
You what pairing would've fit the "Want Versus Need" setup if the series wanted to go there? Zutara.
If I had to guess their "Want Versus Need," they would be...
Katara
Want: To be useful, needed, and to protect everyone around her.
Need: To accept that she can't carry everyone's burdens alone and that she is allowed to be vulnerable, angry, and take care of herself.
Zuko
Want: To regain his honour by capturing the Avatar and earning his father's approval.
Need: To realize that his worth does not come from his father's approval and choose his own identity.
Those arc challenge and balance each other out better. Katara would force Zuko to confront the harm he has caused and prove he has changed. Zuko would understand Katara's anger and help her confront the difference between justice and revenge. Both characters would have to let go of the things consuming them, growing into better people in the procress.
A/ang and Katara's romance is about fulfilling his own selfish desires. Zuko and Katara's potential romance is about growth and transformation. Any good romance in a story should be the latter.
While it's not a requirement in my eyes for zutara to become canon in order for the show to be good, having none of the relationship be "confirmed" at the end would've been much better than that as well. After all, they are kids who experienced something traumatic, so it might take them a while to reach that point. But if the original never existed and I was showrunner, if I decided to add in a romance, that's the one I would go with.