Non-optional, returning players, this is your new server.

[MistakeNot]

Then they need to reactivate the old data centers and move the returning players there.

The old data centers don't exist any more. They can't just "reactivate" them. Creating new datacenters (at the old location or elsewhere) would take some weeks as an absolute minimum - and by that time the problem will have solved itself since by then not everyone will be trying to play all at once.