Mrs. P - I don't doubt that they will bounce back in the FD but the fact that they switched SDs is a bit worrisome...go SHIBS!
It's possible that they didn't want to be compared to Giles and Portier, who introduced their Mary Poppins SD earlier in the season. But that is sort of a dumb reason -- I actually think they would do their own great version.
On the other hand, they might be trying to get out of the box and prove they can do different types of programs.