I watched a ton of Japanese anime and US animation growing up in the 1990s and 2000s. And I occasionally still watch a modern one like Attack on Titan although I rarely watch any series anymore. It’s just the occasional movie or book now.
But one thing that always provoked me, even as a kid, was when they made the hero in a dark story too kiddie. As a kid, I wanted to see teenagers or adults, not kids. And now as an adult that occasionally watches a show with younger family members, naturally I don’t just want to see kids now either.
I’m happy to rewatch old Disney movies because they don’t suck. People die. Shit gets real, and quickly. And yet these are kids movies.
Like, Kora blows Aang away in terms of realism in terms of how serious the surrounding context was. Aang’s story plot was deep and involved combatting genocide, for example. His entire ethnicity was rendered extinct (“The Last Airbender”) and it was about to happen to others, and there were deep plots on ethics, and yet this is the kid we have to watch for sixty episodes. It was a story about genocide for children, involving children. Couldn’t we have made him a teenager at least, so that when he fights men it is more believable? Meanwhile Kora was far more interesting and realistic, because she had a similarly severe set of surroundings including political intrigue, war, murder, torture, suicide, etc, but she was aged appropriately for that context to not be utterly distracting in terms of (even magical) realism. 
