If it makes cleaning a sensor easier and safer then it could be a feature. I doubt anyone would build a camera where the intent was to add a better sensor later - but then it might be the same thing as a standard CPU socket and your choice of chip. Hmm.
You know many times I've thought about buying a digic 5+ and putting into an older 1D and seeing the frame rates skyrocket! Id love to modify or upgrade the camera vs buying new ones all the time, buy a new rear LCD review screen with more dots. I love modding things and hate that I don't know a way to mod my camera