If we had to make a list of Rainbows End characters from most jerky to least jerky, #1 would definitely be Robert, but #2 would be Miri Gu. Sure, Alfred Vaz tries to take over the world, but at least he's not a jerk about it.
Like Robert, Miri is not afraid to share her mind, which often means calling other people dumb: Fairmont High is full of "dumbheads" taking "loser" classes (3.87, 99); Juan Orozco is "like most in those classes, a dumbhead" (10.27), Louise Chumlig is a fine teacher for boneheads (13.64), etc.
Miri is not always easy to get along with, but don't take our word for it. Even her loving parents call her the Little General (2.28, 34) and tell her that she's "too bossy" (7.29).
And her grandmother Lena puts it pretty bluntly when she itemizes Miri's problem:
"Miri can be stubborn to the point of being an asshole. She inherited that trait from the SOB, skipping a generation over Bob." (34.83)
What's really striking about Lena's description isn't the cursing—it's that she associates Miri (her beloved granddaughter) with the SOB Robert (her "beloathed" ex-husband). In Lena's world, that's the worst thing you could say about someone: that she shares a trait with Robert.
But let's be clear: Miri may be bossy and opinionated, but she's not as much of a jerk as Robert. Where he wants to hurt people, Miri merely wants to help (13.113). Hmm—who do we know who wants to help people by bossing them around? Oh, right, Alfred Vaz with his mind control technology.
Miri can be as manipulative as any of the other characters, but Miri always has a very "community"- and family-minded goal: helping Robert join the world (instead of wasting his second chance).
Miri doesn't have to "change" as much as Robert does in order to become a better person; but Miri does change a little. Whereas in the beginning she thought Juan Orozco was a dumbhead, when she's running from Alfred into the tunnels, she finds herself thinking,
"I wonder what Juan would do?" (23.46)
Some of her ideas have shifted, clearly, if she's thinking about Juan as a role model.
And here's the thing that doesn't change about Miri: throughout the book, she remains super-smart. Robert calls her brainless when he's angry; but when he's not angry (which is rare in the beginning), Robert recognizes that Miri is "very bright" (3.55).
But we don't have to take Robert's word for it. We can see how smart Miri is when she tricks Sharif into helping her (10.36-76); or when she recognizes that the little girl who had all the good suggestions might be suspicious: "Maybe the "little girl" persona was covering something" (10.35). She may not be as good as Rabbit at hijacking Sharif, but she clearly could cut it in the world of international espionage—she could be the next Alfred Vaz.