And reading the Kyoshi novels really puts that into perspective. Korra didn’t ruin Aang’s characterisation. It simply revealed the nature of the Avatar cycle. Even Yangchen created problems for the avatar that came after her.
She's still learning and growing. Sure, she's an elite warrior but she's also a teenage girl: a line that is unfortunately missing from the live action. Suki is unapologetically a girl who is still finding her way in the world. And she's navigating the complexities of a war. Of course she's not going to be the most functional teen.
Asami gave up the only family she had left and her immense wealth and privilege to do the right thing. She chose to risk everything rather than help her own father commit atrocities. And regardless of how much she struggled, she persevered and set out to redeem her family name.