So we need to rearchitect MMORPG to separate IO requests into a separate process - which might be not easy for game developers writing portable code.
So they'll probably going to write a 'filesystem server' which will have to do path sanitizing, permission checking and so on. Then one might think, why not write something like PulseAudio - a central filesystem server that can be reused by various software so each software won't have to reinvent it. Do you see where we're heading?