The Lion King 2 is the only sequel media that's allowed to make the former main character a kinda bad parent bcs that's the only time it's been done right. This sounds insane but LoK wishes it had what The Lion King 2: Simba's Pride did.
Anyway the REASON it gets a pass is because it actually grounds Simba's bad parenting in things that it would make sense for him to be worried about or reactive too based on the trauma he's gone through, and on top of that he still gets to have a character arc despite not being the main character that follows from the character arc he had in the first movie.
I don't believe Aang was a bad father in the way the show said he was because it's contrary to his entire personality. Someone who helped form the Air Acolytes would never neglect his son because he's not a bender or his daughter because she's not an air bender. Just like I don't believe Luke "There Is Still Good In Vader" Skywalker would try to kill his nephew, it's contrary to his entire personality, Luke would not see his nephew any differently than he saw Anakin, especially when he hadn't yet done anything wrong while Vader had genocided half the galaxy and murdered a bunch of children.
I believe that Simba struggled to raise his daughter because he was overprotective BECAUSE he knows how fucking easy it is for someone to die in the savanna. It happened right in front of him. He also didn't get raised to adulthood with his parents so ofc he's not the best as knowing how to talk to his daughter or explain things to her, he got raised in the wilderness by two gay weirdos. Of course he's insanely hostile to outsiders including the lionesses that decided to follow Scar, Scar killed his dad and nearly caused a collapse of the local ecosystem. And during the course of the movie he has to actually come to terms with how he's letting his trauma control him and it's drive his daughter away. He gets to apologize and admit he was wrong, he gets to grow.
And yeah you could argue we don't really get to see Aang or Luke interacting with their families because that's not when the story is set but there are still ways to make sure your characterization is consistent, and I'd argue in cases like Aang and Luke where you don't get to see them when they were raising/interacting with their young families it's even more important for you to keep the characterization consistent because we don't get to see the character grow and change we just see where they started and where they ended up, so if you change too much it's gonna feel weird.
You can do the "they grew up to be bad and/or flawed parents/guardians" thing without it feeling like character assassination and for some reason The Lion King 2: Simba's Pride does it better than most media that tries it.
