Let's get OS 4 out the door before we start worrying about OS 5.
But since you asked I think asymmetric multiprocessing (grid computing) will become a reality on the LAN level before the global filesystem takes hold.
I doubt there will be any productive advantage to a 3D accelerated OS but I think some good old-fashioned screen dragging will make a comeback.
As for the merged SQL with the filesystem I don't think that will hit Amiga until SQL or MySQL or some equivalent is ported to Amiga OS 4.
