I much prefer Joss have a blank canvas to work on, rather than feel tied down to decades of material. This is the best way to go, as far as I'm concerned.
I can't wait until the day Matthew McConaughey is cast in a CBM. All of a sudden, everyone will just forget the Oscar he just won and the good **** he's done recently, and start screaming at the top of their lungs about them casting the guy from "Failure to Launch". Are you happy now, Libido?