With regards to concept art, that's an excellent idea. I have already started to go out and get some photographs for the eventual graphic designer to photochop up, but they are still few and far between, and I haven't really put in the requisite effort.
Recurring Visual Motifs:
Cards and Poker Chips
Illicit Drugs, esp. pills and syringes
The world as a game
Parasites, esp Worms
Blood and Money together
Handguns = swords and daggers
Longguns = spears and lances
Hyper realistic photojournalism
Glam goth juxtaposed with unsettling social realism
Art for disturbed children
Mugshots, line ups, and crimescene photos
Still-lives from the homes of the mad, monsters, vigalantes, radicals, wannabe demonhunters, the depraved elite, addicts, and criminals
Sterile charts and spreadsheets
Most of this imagery will occur in interface backgrounds as the entirety of the game is in either isometric game grid or in text/chart based interface.
As far as level design goes, I envision the game eventually being almost entirely a sand box procedure affair where the city is built around the actions of the populace and the legislative priorities of the city council. Bus routes, sewage precincints, zoning, and road planning will all be handled by seperate ai's that create a city optomized for what ever activity the legislature deems most important. So, level designers may only be necisarry initially, unless there are single player mission. My plan is to first develop the combat prototype and a text adventure that tests the morallity system simulataneously, build and economic sim with morallity system, incorporate group consciousness, legislation, and procedural generation into said economic sim, THEN implement combat. Setting up the conditions for when civilized society breaks into violence organically is going to be one of the toughest challenges. After all this is done, I imagine, supernatural elements will be added to differentiate the PCs from the NPCs, but prior to this point the prototypes should be simple enough that the ai's should have all of the same options as player characters.
Player compete over blood, money, and access to useful mortals. AI lives and breathes in the sandbox and has all of the nonsupernatural methods of manipulation at their hands. Player characters actively seek to degrade their principles because they are an obstacle. They have to split blood between increasing skills and resolving their dissonance. AI completely run the world and the groups are just an extension of their actions that allows them to work together and pretend like they aren't disobeying their own code of conduct.
Groups form around shared goals and principles. Business Groups attempt to carve out a niche in this hostile market, but the cards are always stacked against them unless they resort to illegal means. Religious groups espouse principles, provide charity, and resolve dissonance. Charitable groups provide a means to buy off cognitive dissonance. A group becomes a front when it's actual objective differs from any of the acceptable actual objectives for the group type, but the nominal objective remains acceptable.