Gathering everything that has been said, I think here's something that most people could live with. Yes, I realize it will be unpopular still, but frankly, if we don't do anything, the game will run into the ground. Please read this in full before you comment:
On the island(s) picked for armageddon, we will implement some kind of "slow" destruction (meaning a few months at most from start to finish). There is a bonus for holding on and surviving. Something along the lines of honour and prestige gains for everyone in a realm that still has more than half their original regions (or something like that, just thinking out loud there).
Some fully-automated outside force will push realms down. A combination of starvation and monster/undead spawns would be fairly easy to do. Rogue regions can not be taken back - what is lost is lost.
However, we realize that people hate losing their realms and social connections. So every realm can retreat in an orderly fashion by declaring a target island. We will manually re-create the realm there and those who flee can join it. Details TBD (landing location? how to get a region or two to get started?). This way, people can move to a different island with their entire realm. Sure, you lose your land and all, but the people are sitll there and you can rebuild.
The longer you hold, the more you win, but if you miss the optimum point to leave, you will make your re-start on the target island more difficult.
This is just a thought, nothing has been set in stone. But do let me know your thoughts.
