Her actions were far worse this year than they've ever been before and her motivations became totally selfish and not for the greater good like they were in Season 1. It is easier to excuse the behavior when it's motivated by saving people from a terrorist attack but not so much when it's to save her possibly reformed terrorist lover boy.
I don't think Carrie was only motivated by proving Brody was innocent. I certainly think that was a factor, but not the only one. Some of Saul's reasons were her reasons, too, though I don't think she's as idealistic as he is. When Carrie tells her father in 3.01 that 219 people died because she missed something, I totally believe it. That's a part of why she put herself through those awful things at the beginning of the season.
Carrie has pulled some crazy shit in all three seasons. I mean, within the first twenty minutes she is breaking into Brody's home and setting up illegal surveillance. I'd argue that's probably the most insubordinate thing she's ever done (but it's a long list, so I might be misremembering).