The more I think about it the more I realize that my problem with Su is that she’s put on this weird morally superior ground throughout the show where she is never ever in the wrong about anything and we are intended to side with her always.  Lin’s grievances with Su are treated as completely unreasonable and unfair meanness rather than anything Su needs to address and all that actually needs to happen is that Lin Gets Over It (she talked to her mom about it decades ago though so it’s fine).  Su’s refusal to be involved with the Earth Kingdom turmoil despite being in a prime position to do something important and positive is unquestioned and framed as the correct and wise position.  Su’s utter coldness towards Kuvira despite their supposed connection is completely justified, or not even grievous enough to be called out by anyone, since she betrayed her adoptive parent figure and that’s always been framed in the Avatar series as an action that can never be repaired, except for when it has and was indeed a key element of a certain character’s growth.

There’s just some stuff about Su that rings really false, specifically that for someone who had a sketchy childhood who made some bad decisions which had lasting effects on the people around her, and for whom forgiveness was supposedly an important thing along with growing into ‘a better person,’ she can be exactly as bitter and unreasonable as she regarded Lin, but instead of the narrative reflecting on this as a character flaw or an area of needed growth, it’s just ‘the right choice.’  Really, she’s probably the last person who should be disgustedly calling Kuvira a dictator, considering not so long ago she didn’t have a problem with having a personal Thought Police Lie Detector in her supposed politically and socially progressive utopia (a thing which, despite having obvious parallels to the super-corrupt Dai Li, is never framed as a morally questionable thing or even dubious on its own regard— only that he himself was untrustworthy seems to have been the only issue with that)

And really the thing that caps it all off is that maybe some of this could at least be somewhat acceptable if Su’s appraisal of Kuvira were framed in a way that accounted for their intended dynamic— her anger with Kuvira coming from a place of a disappointed teacher, or even a reflexive distaste at seeing a part of herself she wants to think she’s gotten past and doesn’t exist anymore showing up in Kuvira— but for all intents and purposes their interactions may as well be between two strangers.  The Su/Kuvira duel from three episodes prior, despite being visually impressive and inventive, is profoundly lacking an opportunity to bring what should be a meaningful conflict between them to the forefront of the action, despite being the first actual fight between them since Kuvira left.

In ATLA, family dynamics of all kinds were not a small thing, and were more often than not treated with close attention and honesty.  It’s also been important in Korra.  So when we get Su’s complete icy coldness towards her prodigal student, who she asserts was “like a daughter” to her, the dissonance is hard to ignore.

Because it feels like Kuvira stopped being that to Su the minute she no longer had her absolute obedience and loyalty, to the point where her very life is forfeit for her to be morally right to take, and if you ask me that doesn’t seem very much like the surrogate family of the morally conflicted Zuko and patient Iroh.

It feels a lot more like Zuko and Ozai.