The old team was getting a little boring, and there was so much backstabbing going on from Chase, that one of them had to go eventually. And it would have been a crappy series as Chase MD. I think that putting them into new positions adds a different element. They're still there, and they're still able to involve themselves in the storyline. Chase's animosity for House plays out very well, and Cameron's episode as the standin dean of medicine was an excellent episode.
As for the new team, I'm sorry to say that I'm disappointed in Kuttner. I really like Kal Penn, but every episode it's all about him ignoring the medical case and wondering where their missing colleague is, and whether or not they got laid. Taub is also falling into that rut on occasion.
The Foreman and Thirteen relationship, I'm not even seeing as being focused on being inter-racial. I'm seeing it as being an intrigue element for House, as well as an Intrigue element in the character of Thirteen who is by confession, bi-sexual, and how that plays into things.
Personally I hate the relationship, because it's between my favorite non-House character, and my second-to-least favorite character. So yeah, I'm a little disappointed in that.
Overall after this last episode with the Methadone, I'm still entertained, and I'm still looking forward to new episodes.