Things like justifying Aang's reasons for abandoning his people and running away wouldn't have been portrayed as a negative aspect of himself because it's understandable that he didn't want that power and wants to run away from the responsibility levied upon him because of his birth. He never faces the realities of his choices, like finding Monk Gyatso's skeleton in the original series, because that challenges his moral choices and we can't have that.
The Fire Nation gets absolutely no sympathetic scope to view them for and are complete monsters. Iroh is retooled into his original conception of purposefully teaching Zuko wrong to humiliate further in regards to his father and sister, who are insane tyrannical psychopaths with no deeper meaning informing their actions. Zuko also ends up being closet gay because the fire nation hates gays.
Katara becomes the character to grow and 'improve' while outstripping Aang and anyone else in competence. The fan will wonder why she can't be the Avatar instead because at least she isn't a whiny fucking pussy like Aang.
Sokka is the one who is always 'wrong' and a no-fun asshole that tags along with the group because he mistakenly believes in masculinity and protecting his sister. She often saves him and protects him instead. At the end of the series he learns his lesson and also embraces that he's gay with Zuko.