The whole time I was reading this thread two ideas came to me:
Númenor, also called Elenna-nórë or Westernesse, is a fictional place in J. R. R. Tolkien's writings. It was a huge island located in the Sundering Seas to the west of Middle-earth, the main setting of Tolkien's writings, and was known to be the greatest realm of Men. However, the inhabitants' cessation of the service to Eru Ilúvatar and rebellion against the Valar led to the downfall of the island and death of the majority of its population.
We could have our very own Numenor. The gods are angry at the crimes of men. Players have the option to emigrate to another island (thus no ones characters are forced to die if they leave). Your character has the role play equivalent of being from Atlantis.
Someone also suggested dragons.
My idea was for dragons to be a third spawn option for hordes (in addition to regular monsters & undead.) The number of dragon spawns can be set by the devs. But unlike normal hordes, dragons are not so easily slain (maybe Heroes can start earning their titles?), have a very large appetite for gold (I.e. YOUR gold) and are difficult for an ordinary army to kill.
You can also have an icon on your map that stands for "Here there be dragons!"
It makes perfect sense to have the world grow a little wilder as humans are fewer and less able to tame the land they live on.
