I just finished the show and I have many thoughts. First, I want to say that I was not expecting a shot for shot/frame for frame remake. I have no problem with some changes or improvement on original material. That being said, I have a problem with changes that either make no sense or take away from the story.
My main problems were
-The change with Sokka and his personality- In this show, he is a competent warrior who looks over the tribe. This would be fine, if it actually made sense for his character. In the original, Sokka in the first season is an immature and incompetent "warrior". He is sexist (and this is always called out) and he is quite prideful. Over the course of the show, he finds his skills in creating plans and proves to be quite valuable. He also ends up learning to fight with swords. Most importantly, he learns from his sexist ways and grows. His original personality is one that fosters his character growth and development, to remove it means that there is no real understanding of how his sexist beliefs and immature behavior fosters his eventual growth and character arc. This personality change in the show also does not make sense because he does not look over the tribe. In the original show, Katara is the one that does everything due to her motherly and nurturing qualities (which they removed by the way). It's even said by Sokka in the original show that he can't even remember what their mom looks like, he only remembers Katara's face, because she is the one who was taking care of him and the tribe. This part is already long so lets discuss a couple more changes that I dislike.
Katara's personality change and her overall dullness in this series- Katara was one of my biggest complaints in this series. They have removed her nurturing and motherly qualities and have completed toned her down. She is no longer fiery, she is a girl who is unsure of herself, and a girl who practically listens to Sokka on everything. They've essentially switched the dynamic between Sokka and Katara and I do not like this change at all. They really thought they were improving on her character by removing some of the most important qualities from her. Her being nurturing isn't a bad thing, it's actually important because it highlights how she was essentially pushed into taking on the responsibility of looking after her older brother, but they've taken that away from her. If you're going to remove something that is so key to her personality, couldn't you at least have made her fiery?
Aang's reasoning for leaving- This is a change that really infuriates me, because this change makes it clear that the writers do not understand the importance of his real reasoning for leaving. For context, in the original show, Aang runs away because he does not want to take on the responsibility of being the avatar. However in this new show, he runs away because he "needed fresh air". I feel like they were trying to be funny but honestly, I'm not laughing. The whole point of the first season is that Aang is trying to avoid his responsibility of being the avatar. It's the reason why they go on so many detours, because he wants to avoid the responsibility and because he's a kid. Taking out the original reason for him leaving means that Aang automatically accepts his responsibility and we don't get to see him learn that even though it's a huge responsibility and weight, he still has that responsibility and he needs to face it.
Some things I liked
-The visuals
-Most of the casting
-More depth to some characters + relationships
It's okay, it's like a 7-7.5 out of 10. The acting and writing needs a lot of work. The visuals honestly are the highlight.