I can definitely say I'll miss Ms. Carpenter - I really liked her character. On the other hand, I'm very wary of Spike being added to the Angel cast - part of what, IMO, makes Angel good is the character balance, and I'm very worried with the removal of Cordy and the addition of Spike that that balance will be thrown off.
I was never a big fan of Spike anyway, or most of the Buffy characters. Or for that matter, the show itself. I'm just hoping he won't overshadow the rest of the cast in terms of screen time.