It doesn’t matter how many servers you have for your MMO, some of them are just going to be more popular than others. That’s inevitable. It happened in World of Warcraft, it happens in Final Fantasy XIV, it happened in City of Heroes. The only games it doesn’t happen are ones that use a megaserver setup, and that has its own issues which are a separate discussion topic altogether.
So let’s just accept that you’ve got an overpopulated server. The question then becomes what you’re going to do about it. Do you offer incentives to transfer people off? Do you add hardware to that specific server to support more people? Do you change login procedures? Do you split the server? There are no good answers, and no matter what you do, something is going to cause problems. So what do you think, readers? How should studios handle overpopulated servers in MMOs?
Please note that if your answer is “not let it happen in the first place,” you’re arguing that the best way to fix a car is to not have it break.