Have Rheinland win the war and completely wipe out all existance of Liberty.
:D
People naturally want to group together. They'll always go where the crowd is. If everyone started in another house, they'd likely group around there. Only problem is the NPCs in Kusari and Rheinland will blow the crap out of a lot of newbies. Even in Bretonia, those Templar and Chimera NPCs are a pain in the ass.