I see alot of people talk about bad retcons in the avatar universe and tbh alot of the stuff they talk about aren't even bad retcons it's just their headcanons being contradicted or folks not understanding whats on the screen.
Like Zukos lightning scar not being present on adult zuko in the aang movie trailer, there is a certain subset of fans who think that they are retconing zukos lightening scar cuz they don't want zutara crumbs or whatever(which by far has to be the dumbest thing I've ever heard" and I have to ask. Has zukos lightening scar ever been treated as a permanent thing in any media post the finale. I know in one of the atla comics on webtoon he has it..but it's completely absent from the physical release of that same comic so that doesn't count. Like truly is zukos scar being permanent not a headcanon thing that the fandom made up? So why are people up in arms at the movie for him not having it.
"Why does aang have his but zuko doesn't?"
1. Aangs scar actually does matter to the story, the lightening entered his back and exited his foot and killed him immediately. He also wasn't headled immediately and needed the magic oasis water to be brought back to life. Not to mention katara had to keep healing him for weeks even after that and she literally says he has a whole bunch of energy knotted up in that specific spot
2.Zuko on the other hand had successfully redirected most of the lightening it just passed through his heart in the process and after katara dealt with azula quickly and after she healed him he was back on his feet immediately.
Plus most lightening scars aren't permanent anyway.
Then you have the whole original benders being contradicted by the lion turtle thing and it's not even a contradiction.
The lion turtles gave the humans the power of the element but didn't give them mastery over it and you can see that in the Wan flashback that the humans just haphazardly tossed the elements around willy nilly there were no bending styles before Wan became the avatar.
And thats where the original benders come in.
The original benders are the dragons, sky bison, moon and badger moles and the humans developed their bending styles by watching and studying how those creatures moved originally because as we've seen with katara naturally being a bender doesn't automatically just make you good at being a bender.
And we even see it with Wan and firebending when he was doing the Dancing dragon in the spirit wilds the same firebending form that zuko and aang learned, they even said that after that he started using it like an extension of his body.
So yeah the lion turtles gave the bending and the humans developed the bending forms by watching the original benders. No contradictions here plus Bryke said exactly this on the braving the elements podcast.
Then you have the whole "element opposite to the avatars personality thing" which seems to be one of the most common ones as of tlok cuz people say it doesn't make sense that korra had difficulties with air and I think they just greatly misunderstood bitter work.
Katara using air being the natural opposite of earth bending to explain to aang why earthbending is so difficult for him isn't her literally saying you airbend therefore earthbending hard cuz by that logic every airbending avatar would have difficulty with earthbending just off them being airbenders. It's her using the elements to directly relate to aangs problem cuz even later in the episode toph says that aangs problem is that he's thinking like an airbender and not an earthbender. Airbending is rarely ever offensive, it's all about be patient and dodging and disorienting your opponent , avoiding actual head on combat which is LITERALLY just aangs nature we've seen aang run away from his problems and try to avoid conflict all the time and well thats not something earthbenders do rock is stubborn so you need to be stubborn as well, you can't avoid or dodge you need to be prepared to take that boulder to the head if the situation calls for it and thats something that aang wasn't familiar with, it's not until after he successfully learns earthbending that he actually starts being more head on in his confrontations.
So yeah korra having difficulties with airbending cuz of her more headstrong and hot headed nature makes sense you add the fact that airbending is an extremely spiritual element and korra was not that spiritual at the beginning of her journey and you can see why it was difficult for her.
And lastly Katara being an accomplished healer and a grandmother in tlok isn't bad for her character.
Katara never hated healing she just didn't want to be forced to be a healer. Katara was the last waterbender in the southern tribe and was only aware of waterbending as an offensive style which is why she trained herself in offensive waterbending and on her journey she found out that she had the ability to heal purely by accident. Now look at it from her perspective imagine teaching yourself one thing to the point where you're better than most masters at said thing and then along your teaching journey you found out through pure accident that you could do this other thing as well,you finally made it to a reputable teacher to learn the thing that you've spent most of your life trying to teach yourself and said teacher tells you that because you're a woman your worth lies in the thing that you figured out you could do on accident and not the thing that you've spent tireless hours trying to master. Of course she's going to be upset but she's never hated healing, she just didn't want being a medic to be her only contribution to the 100 year war. We even see that she has alot of notable healing moments as well as combat moments. Them calling her the best healer in the world isn't them diminishing her efforts from the 100 year war it's just at this point katara doesn't need to be a fighter anymore.
She should've gotten a statue tho, they really fumbled on that aspect for sure.
And we see in the fortune teller that Katara was extremely happy to find out she'd get married and have kids and great grand kids cuz thats the life she's wanted for herself and after all her hard work she deserves that life.