Now that I think about it, her character did the 180 starting with Warren Ellis' Thunderbolts, prior to the Dark Avengers.

You could easily explain her becoming skanky and full-on evil by saying she ended up with the Earth-2 Moonstone instead of her original one, and it effected her personality.

Then you'd also have to explain why before turning her back to her Busiek/Nicieza persona. I sure hope Jim Zub cares enough about the character to try. She so much more interesting as someone who is manipulative and power-hungry, but who isn't necessarily bad and who can care about people. (Hawkeye)

One thing in particular I'd like retconned is having it turn out that Karla killing her mother was a false memory. That came out in an issue of Ms Marvel when she was being attacked via telepathy.

I didn't get very far into the most recent incarnation of the Thunderbolts led by Luke Cage to know how she was handled there.