I understand why some people thought Kiyi was unlikeable in "Ashes of the Academy", because no one likes a know it all, and it's hard to establish a new character in supplementary media. As well as kid characters being very hit or miss, in my experience. But I actually do appreciate Kiyi as a character in the comics.
Of course Kiyi would have more conciousness about the Fire Nation's politics than most children should, her brother is trying to rebuild the nation substantially, she herself has been targeted by a radical syndicate, and she's managed to rather quickly build relationships with notable members of other nations.
Also I find it so cute how Aang and Kiyi seem to have bonded well, considering she is also Avatar Roku's great granddaughter.
Kiyi is placed in this book as the beginning of the fire nation's reform and growth from it's past in the 100 year war. She's posited as a stark contrast to the royal siblings and their peers, as well as the kids in "the Headband". (In fact, I find certain similarities between Kiyi's character in "Ashes of the Academy" and Aang's in "the Headband"). Kiyi pushes back against a teacher trying to frame tha Fire Nation's actions in a more positive light, and questions the system in place. She refuses to be an active perpetrator, but she also refuses to be a more passive endorser and follower of a system, a role we see Mai and Shihan break out of throughout the comic.
Kiyi is supposed to herald in a new, more hopeful are for the Fire Nation, the one Zuko is trying to bring about.
Zuko: I promised my uncle that I would restore the honor of the Fire Nation. And I will. The road ahead of us is challenging. A hundred years of fighting has left the world scarred and divided. But with the Avatar's help, we can get it back on the right path and begin a new era of love and peace.
She's a child growing up in a nation that is still recovering from the self mutilation it went through due to its own imperialism. She's an outspoken and confident little girl who speaks out on what she thinks is right. She has the luck to be able to trust the adults around her to have her best interest in mind, something that her older half siblings, and many kids in the Fire Nation did not have. But that's not really a reason to dislike her.
I also don't really get the "Kiyi is a replacement Azula" thing. Like, yeah, she's Ursa's second daughter, and she shares some traits with Azula, like *checks notes* calling Zuko "Zuzu" and occasionally teasing him. But I think Kiyi is meant to be, once again, a symbol of the hope for the Fire Nation's future, and for Zuko particularly, the Fire Nation he is trying to foster and nurture. Quite literally untouched by Ozai, in a way, since Kiyi is the only "Fire Sibling" to grow up without being harmed by Ozai, at least directly.
I also just don't buy the "Ursa replaced Azula with Kiyi" thing. I can agree that Ursa choosing to forget Zuko and Azula and take on a new identity is kinda shitty. But also I am taking it easy on the woman who was forced into marriage to the Beethoven of Abuse™️ as a teen, sue me. But having Kiyi while under memory loss was definetly not a concious effort to replace her daughter, and from what we're shown of Ursa after she regains her memories, she is very worried and caring for Azula.
Like, do we not think that the fact that she is getting panic attacks over Kiyi not being in sight is connected to the fact that her other daughter is currently mia??? Not even a little?
Note that this does not mean I don't think Azula feeling replaced by Ursa is an invalid feeling. It's something even kids from less fucked up families can experience when having a younger sibling. Adding to this the context of Azula's conceptions of Ursa and her delusions surrounding her, I would be surprised if Azula were fine with Ursa having a new child, let alone a daughter.
But I think Azula's hurt can be valid, while at the same time, Ursa and Kiyi should not be seen as villains in her story. And Kiyi especially should not be hated just because of her asscociation with Azula, or pitted against her. Like that's two children, who both could use a shitton of therapy tbh.
Also, big fan of this scene. Pop off you little icon