I wouldn’t say I exactly hate Kya, but she is definitely a waste of a character that could have been much more. I mean, she’s the daughter of Avatar Aang and his wife Katara. She should have been much more special.
Granted, she’s a water bender, but that’s not really important to the story. We do see her fight and bicker with her siblings as if they were all still children.
I’m guessing the creators meant for her to do more but she just kind of got lost in the middle of it.