Gail Simone fired from Batgirl, implies it's because she refused to fridge somebody.
All things considered it's not the major shakeup that Berger's departure is, but it's a shabby damn way to treat a beloved writer (and, not to put too fine a point on it, one who sells books).
On the whole, Simone's been a pretty damn good soldier despite all the bullshit DC's heaped on her and its other creators in the past year and a half. She's expressed some dissatisfaction at being taken off Suicide Squad, and with editorial decisions concerning Firestorm, but she hasn't engaged in anything approaching the (honestly pretty mild) complaints of Roberson, Langridge, or Wood, let alone the gleeful adolescent bridge-burning of Rob Liefeld. (I know, I know -- "gleeful adolescent ____ by Rob Liefeld" is a tautology.)
Regardless, she'll land on her feet. Maybe it'll be at DC and maybe it won't -- on the one hand, I'd love to see her do something creator-owned over at Image or one of the other publishers; on the other, she's probably the most visible example of a dissatisfied DC fan working to change things from the inside, and I think it would be a real blow to lose her in that capacity.
Ah, who the hell am I kidding -- you know what my vote is. Keep on shooting yourselves in the foot, Warners -- I'm happy to follow your disillusioned creators to whatever creator-owned work they cook up.
...Well, maybe not Liefeld.