She does four things that I can see. One is to talk about how Indians used to own the land, but Rainwater does that and does it better. The second is to worry when the kid is in danger, but Kayce and John do that, too. The third is to be the one to make sure viewers know that the ranch isn't necessarily the good guy. Plenty of antagonists say that, but they are enemies so it doesn't help the viewer. The problem is that (a) she already hated the Duttons so she can't really be the conscience, and (b) it's always bundled up in "150 years ago this was my people's land", so again she has a personal grudge. The fourth is to emote on behalf of all these other stoic characters. She does that pretty well, but it has to be in small doses, otherwise she comes off like an emotional punching bag.
There have been a handful of moments that I thought she was good, but they are few and far between. She doesn't DO anything, she needs to be an active part of the plot or stop getting screen time.
