One thing that I feel would be cool is if there are NPC heroes and villains roaming around the area kinda like the villains seen in Brickstown. You could have the heroes on the villain side working to clean the area of villainy while the villains on the hero side of the zone work to bring more crime/influence to their side. These heroes/villains would not belong to any group/organization, instead setting their own paths. With these characters, I would set them up similar to the prisoners during the prison break zone event in Brickstown in terms of levels. You could also give them minions/sidekicks like regular mobs, but tailor to that specific villain/hero.