I really do not like this at all. Specially when we are looking into the future where more copies of the game will be bought because it gets better and better reviews.
So just to start up, lets say X of the current population pre ordered the game. And in the coming months, Y of the future population will buy the game. If with only Pre Orders we filled every server, how are you going to manage the servers when more copies are bought?
This is a major problem that will turn into a HUGE damn problem in the future.