The other problem is that they would have to 'pause' the entire game while the physical move was in progress, otherwise players would still be able to move around in the rest of the game world (other than the cluster of stars they took offline to move them). As I understand it, this is already sort of a problem with the Time Dilation mechanic they currently use; time moves at 10% normal within the fight, giving people outside the slowed-down star systems time to deploy forces at 10x speed relative to the fight.