It sounds like the kind of game where you go to sleep in your apartment, and wake up, and go through your email, pay a couple bills, go out and eat at a noodle shop, and maybe witness a gang shooting or background explosions - and choose to investigate or not. Which would be pretty awesome.
I think this would do well as an extremely-detailed environment, where you can for example hack a soda machine, turn on a jammer and prevent nearby cell phone calls, see trash blowing down the street, watch as potholes fill with water when it begins raining, see a child chasing a cat down the street, etc.
I think Seattle is a great choice because it has an underground, although many other cities do too: Edinburgh, Portland, probably others. You could use a fictional city, putting anything in it that you want. Shadowrun also did well by having various neighborhoods that ranged from ultra-modern and with heavy police presence to "barrens" areas like the worst of Detroit or post-flooding New Orleans.
I would suggest picking up some Shadowrun books. I'm reading one on corporations and their histories, and from it you could easily create some random event tables that build up to a procedurally- and randomly-generated corporate profile, with top shareholders and board of directors, subsidiaries that got bought out, chance for a name change that combines both company names vs. leaving the subsidiary as-is to distance it from the main corp. And then, the opportunity to have new events happen that change those features of the corp, appear in the news, and spawn adventures.