As of episode 4
I like Christa a whole lot better. She's becoming a better rounded character and if you side with her or go for a solution in the middle she actually appreciates it. I was afraid at the end of episode 3 that we would have Lily the 2nd on our hands but she has become a better rounded character in my eyes. In episode 3 I would have never let her be the one to go with Clem in the end (I always knew Lee had a huge chance of biting the bullet), but as it stands right now I would. Well after getting rid of Omid because he seems as helpful as Ben at this fase. Plus seeing how Carley died after you barely see her in episode 2 and you barely see Omid this episode I don't think Omid has a long life ahead of him.
I have the feeling that in the end you will have to make a choice as to who gets to take clem and there is no way in hell any of the others is going to take her.
So yeah for her to make that change from "oh hell no" to "why not" means she was a whole lot better written this episode. Although I am afraid she is pregnant and that could pose some problems.