Ugh I will always love the concept of Katara using blood bending to revive Zuko after the last agni kai, mostly because it makes no sense to me that Zuko was able to bounce back so easily after being struck by lightning, but also because the way the show treats bloodbending is just odd to me. It was a defense mechanism created by a traumatized victim of some of the most devastating parts of colonization, and although I understand that Hama was supposed to symbolize the "bad parts" of waterbending and was important for Katara's growth in realizing that the world isn't entirely black and white, its still disappointing to me that the show never explored the gray areas of blood bending, especially since that episode was, as I stated above, about understanding the gray areas of the war. Katara using blood bending to revive Zuko would add so much to the last agni kai in demonstrating that she has truly realized that "good" and "evil" are relative concepts, and Zuko being saved by both a defense mechanism of a survivor of colonialism and a type of bending used to terrorize his people would have even added to his arc, as the narrative required him to save and subsequently be saved by the physical embodiment of everything his family sought to annihilate.

The context of Katara using bloodbending in TSR is so important, but people just boil it down to “Katara was consumed by her rage”. The only episode in the entire franchise that treats bloodbending with the nuances it deserves btw. She willingly used a technique that she was once forced into learning but was developed by one of the last bender’s of her tribe to escape a Fire Nation prison on a Fire Nation soldier who she thinks killed her mother because he believed she was the last bender of the SWT. She did not bloodbend other soldiers on that ship and she stopped as soon as she realized this man was not the soldier who killed her mother because it wasn’t about wanting to scare him or hold power over him, it was about reclaiming a part of herself and her history that she had lost both when Hama forced her to learn bloodbending against her will by putting her friends in danger and when her mother was killed. Did she hold power over him in that moment and did she scare him? Yes, but that wasn’t the reason she chose to use bloodbending in that moment. If she had chosen any other form of waterbending to restrain him and threaten him, she would still be holding power over him and scaring him too. In fact that would show more intent to hold power over him and scare him than bloodbending him did because those other bending techniques don’t have the added weight of how and whom they were developed by.

sometimes I forget that bloodbending having medicinal purposes and being able to help people medically isn't actually canon like what do you mean Katara didn't discover a way to help people with heart conditions and blood clots and internal bleeding and revive those whose hearts have stopped and open up hospitals around the four nations with teaching academies for life-saving medicinal bloodbending for waterbenders