Lord help me, I loved it as a child and I never looked at it with a critical eye. I will always complain about a magical turtle beast coming out of nowhere and provide a convenient solution. I don't really have any complaints. The most critical analysis I get from it is looking at it through world building perspectives with Hello Future Me on YouTube. In that sense, I think they did a good job on Azula's characterization, their magic system, etc. I think, with the amount of effort they put into these elements of story telling, it was destined to disappoint. It takes a lot of bandwidth to create a tight story that encompasses the full breadth needed to take on a political philosophy like antifascism. It's hard to fit in sea monsters, kyoshi warriors, penguin sledding, etc. and then pivot into that.