Solution to Overpopulated Servers (such as Balmung)
1 - Develop criteria for when a server is considered overpopulated and it gets this procedure. An easy criteria: when there is no longer any houses or apartments that can be bought and every single one has been purchased in all districts of all wards. This would mark a server as 'full.'
2 - Give a 30 day notice that the server is going to be split. During this time, there are no changes to the server. People can continue to play on it like normal. No transfers, paid or free, would be able to set this world as a destination, during this time.
3 - In the mog station or somewhere similar, set up a "pick your world" page between two not-yet created worlds. It would indicate the world you are currently assigned to, that everyone in your FC is assigned to, and who everyone on your friends list is assigned to. A default would be assigned by giving priority to sticking with the FC and friends list, however you would have the option of switching your choice as many times as you like during the 30 day period. A currently subscribed account would not be required in order to make your selection, and an e-mail advising of the split and how to pick a world would be sent to all accounts which have a character on the world and of course purple text in game to announce as well, several times daily for the entire 30 days, including a message for the user's current choice
Some options that could be picked: A: Same as FC (default for anyone in an FC except its leader), B: Same as friends (would keep the most friends possible after split), C: Same as X friend (pick a friend and copy their choice so you'll be on the same world as them no matter what, even if they change their choice last second) D: Recommended (would pick the world with the lower population, default for anyone not in an FC, or an FC's leader and FC would follow), E: Pick one world F: Pick the other world
The system would "soft pick" a default using A or D categories, but would not automatically change should predicted population levels fluctuate. If one of those choices is "hard picked" by the player, then it would automatically change as the predicted population levels fluctuate, or if the FC picks a different world, for instance.
Each character on the world would be able to make a different selection. In option C, you would be able to pick one of your other characters as a 'friend' to follow, to keep your characters on the same server.
4 - When 30 days is up, the transition should essentially be seamless. You go to log into your character, it is exactly like logging into the old world. You still have all your money, all your gold, your house is in the exact same district/ward/plot, nothing has changed for you at all. Except everyone who went to the other world is now gone. All the houses belonging to people who went to the other world will become available, etc.
5 - Once the dust settles, the normal free transfer availability will be available for anyone who wants to transfer off of either of the two new worlds...except the only world they can't transfer to is the other half of the split. This free transfer eligibility would remain until the next split happens within that data center (at the end of the 30 days, not when the split is first announced.) After that, they could do a normal paid transfer to any world, including the one that was previously restricted.
6 - This process would repeat as needed, but with only one server at a time per data center experiencing a split. If another server fills up, it will wait until the first server's split occurs, then announce its 30 day timer.
7 - If a world that was created in a split is the very next world that becomes too full, then options E and F for picking a world (see point 3 above) are disabled for that split.