I have read in at least one LJ that people consider the characterization of Hermione Granger in Book 5 to be "bland." That her role was to be "always right" and nothing more. I'm more in line with the many others who find her to be amazing.
Hermione has always been an anomaly in Gryffindor, where rules are meant to be bent, so long as no one is hurt. Hermione has always pushed to obey the rules, although she mellowed fairly quickly in SS/PS. And even now, she's a prefect and thus has the authority and mandate to enforce the rules. She's always seemed only a couple steps away from Percy.
In this book, Hermione Granger's goals were to not only remove Umbridge's regime from Hogwarts but also to topple Fudge. This is not something a bland, prissy girl who is focused on obeying the rules would do.
And she starts this at the Opening Feast, where she actually listens to Umbridge's speech, understands the subtext and passes it along. I'm convinced she discussed it with McGonagall because of a remark McGonagall made: "At least you're listening to Hermione Granger." This doesn't disobey the rules, but it does start people *thinking*. And people thinking is the worst thing for any fascist regime.
She continues this in Umbridge's first DADA class. No one else noticed the lack of practical work until she pointed it out - and then the whole class erupted. She probably didn't count on Harry getting as upset as he did, but Harry's anger is a character all its own in this book - and she eventually uses it, even if it means he has to suffer through Umbridge's horrible punishment.
As an aside, anyone notice that Umbridge now owns several rolls of parchment covered in Harry's blood? Or the blood of other rebels, such as Lee Jordan? And that blood is used in spells in the HP universe? Dark spells? Something to think about.
Her first major act of rebellion is to form the alternate DA class, and to recruit Harry as teacher. It may not have been against the rules when she formed it, but she had to know it would be afterwards - Umbridge reacts instead of acts. And that it would be dangerous for an untrained teacher to lead such classes.
Not that Harry was dangerous. In fact, Harry is an excellent teacher who takes real pride in his students' accomplishments and who thrives under the responsibility in a way he never has before.
However, this not only provided the necessary training to pass the Owls and to protect themselves, it also formed a revolutionary cell of people loyal to Dumbledore and to her and Harry. By jinxing the original signup sheet, she even ensured their loyalty - and created a means of identifying traitors. That, btw, is scary - Hermione is definitely one of those who believes the ends justify the means. She's as ruthless as Dumbledore. Good thing she's on the side of the Light, isn't it? She does the same by copying Voldemort himself when she creates those coins.
And Dumbledore is very ruthless. I'm currently convinced he knew exactly what would happen in the Occlumency classes - not only that it would open Harry's mind further but he'd also pry into the Penseive. After all, he's done that in the past.
I'm currently, in my rereading, at the point where Hermione has made use of Umbridge's paranoia to counteract the Ministry's disinformation campaign in the Daily Pravda.(1) And talk about ruthless. After she realized that the students of Hogwarts wanted more than lies and have figured out something is fishy about the reportage of the ten Azkaban escapees, and has extrapolated that their parents and the rest of Wizarding Britain feel the same way, she takes the tools she has and begins her own campaign of information.
Because information is key when all around you are working to hide it - including well-meaning adults on your own side. She doesn't ask anyone's advice, either. She calls upon a woman she despises (and controls very thoroughly) and a girl whose father edits a publication she considers utter rubbish, forces the one to write the truth and for free and submit it to that publication, and does so by sitting back and allowing Harry to relive one of the worst moments of his life. She does so knowing that, in their thirst for truth, the wizards will snap up the Quibbler - after all, it would be like a well-known New York Times reporter writing for the Midnight Globe. And also knowing that they will then call on the Ministry for more information.
She also had to know it would cause Harry to be tortured more, and that it would cause the magazine to be banned. She counted on that last - displaying a knowledge of both Umbridge and student nature.
Which means she counted on students disobeying rules.
And then she leads Umbridge into the forest, knowing that she will either be injured or killed. And she does so calmly. Umbridge is a danger to Hogwarts and the rest of Britain, after all. Whatever Umbridge's reasons for doing what she's doing, the result would be Voldemort gaining powers.
Woof. Looking at all at that - Hermione is seriously ruthless and quite scary.
(1)Not entirely original with me; David Edelstein in Slate referred to the Prophet as Pravda-like.