It's a twist I dont like. I feel like they already played that "Tony the bad guy" card and it's stupid to do it again. How can there be an explanation this time though, after killing the head FBI agent?
That's why I'm pretty okay with it. I always look for ways Tony could back out and flip to the other side, but killing Moss makes me believe that Tony really is a bad guy, whereas before it wasn't anything important that Tony did that couldn't be forgiven.
Kim coming back is interesting in that I see a scenario where she helps him against his will and she dies during surgery or something... Jack will be without his wife and daughter, and dies at the end of the next season. Shaping up to be a real tragedy.
Then again, maybe I just read too much.