Idea SuggusttionFollow

Ok I don't know what everyone else may think but for me sitting in a city which has no action kinda sucks after a while. My Idea is that in contested areas have group of Mobs which attack the city and which try to take it over. If the mob does take it over then it would have the city as it respawn until the players would clean it out. So you would have a city of hord taken over by <insert Mob Name> which truns it into their new spawn town, which opens up quests for the players to clean out which only has a short time before a whole group comes and cleans them out. So it just an Idea. Suggestions and ideas are welcome.