I hesitate to make the comparison, but this reminds me of The X Files doing a spinoff of The Lone Gunmen. Now I happened to love those characters from the X Files, but I think a lot of people who watched the X Files saw that and was like "eh". I have a feeling that is going to happen now. I think I personally will like this show, but I can see a big chuck of BB watchers not liking it.
Some of these shows are like a Gumbo....you stir up all these elements and it works for whatever reason....but people like it for DIFFERENT reasons. You pull just the chicken out of the gumbo and make it into a taco and half the people will be like...."uh...no".
Then again, you've got the Buffy/Angel thing and that pretty much worked. I actually grew to like the Angel show more because it had more depth to it. So I guess you never know.