Yeah, I'm a Law and Order junkie.
This of course means you have to get used to cast changes. Especially for ADAs - 4 years seems to be the max.
The latest one to be replaced is Elisabeth Röhm. In an episode that first aired in January, she was the first one whose character was fired, and in a strange plot twist her final line was "is it because I'm a lesbian?"
She wasn't my favorite of the bunch, and I wasn't alone apparently - somebody actually had started an online petition to have her replaced.
I don't know if it had any influence or not, but she's gone.