One thing is for sure. It's the end of the show as we know it.
Richard is a great replacement, but Carl and Rory were the original team. Like in Stan & Olio, Tom & Jerry or Pat & Mat. It's hard to image on without the other.
Good luck Rory I hope everything works out OK for you!
PS: The 100th show is out. If you are a developer and didn't yet started to listen to the show, what the hell are you waiting for?