They should set up a queue for people who want to switch to a different sever IMO.

So that even though things are "full" right now, you can still sign up for the server you want to move to and when they figure out how to unjam it, they'll let people go to the server they want on a first-come-first-served basis with a cap. So if you and your friends all apply for queue of the server you want at the same time, it'd be unlikely that only a few of you would make the transfer; either you all would or you'd all be above the cap and wouldn't.