Would be interesting if that did happen. A full reset when it all comes tumbling down? Or a concerted effort with every Noble emigrating to one realm and one continent to drive back the darkness and reclaim it all?
Actually that would be pretty cool!
The way I see it, if BT falls, then other continents should start having invasions just as BT had. And in-between invasions, everyone gets a chance to try to recolonize BT, like at startup, to establish a foothold to push back the evils and therefore prevent them from going back to the old continents.
This, IMO, would open for interesting gameplay and storylines.