[Y]ou could assign each neighborhood some stats. A make-your-trait system like Risus can be handy for this.
declining neighborhood trying to recapture former glory(3) domain of the O'Bryan Mob(2) best bakeries in the city(2)
Heck, you could probably get a lot done with just some encounter tables with built-in change conditions.
This is intriguing, because in my experience superhero gaming has been all about the push-pull between the players and the GM. The players typically strive to live up to their righteous ideals by patrolling neighborhoods and confronting villains before they have a chance to poison the city’s drinking water or plant bombs at the children’s museum. That sort of thing.
The GM, on the other hand, is responsible for driving the story forward with some semblance of a plot. When considered alongside the players’ ongoing superheroism, an overarching plot can sometimes feel like a story railroad that detracts from the players’ own goals and motivations.
Jeff’s idea of sandbox-style play ties this up neatly, especially for gritty, street-level games. Sure, players will eventually want to confront of the head villain behind a particular gang, but sandbox play ensures that they’ll have the proper context and experience when it’s time for the big showdown.
The only potential problem I can see is lack of social encounters to satisfy cerebral gamers – but really, this is sort of endemic to all superhero RPGs, especially the Silver Age ones I’ve played lately. Nice, meaty social roleplaying and intrigue is best packaged as part of a larger plot, which needs to be balanced carefully alongside the players’ motives.