Setting:
As hinted in F3, eastern Massachusetts. Boston & Cambridge (the Commonwealth). Ruins in the east, misty hills & forest in the west. Near Cambridge, an immense energy force field that lights the night sky. The tower that produces it can be seen from all but the westernmost points of the map. Inside, the clean, safe Commonwealth - a facade of pre-war life. Boston is a blasted ruin overrun with monsters, gangs, scavengers and militarized zones manned by British invaders. Hugging the edge of the force field, the fiefdoms of the Commonwealth struggle to survive daily life while producing enough (farms, mines, etc) to pay tribute in exchange for 'protection'.
The fiefdoms are relatively recent; much of the surrounding area was, until recently, too radioactive to loot. Much of the area has not been explored to any great extent. A new tribe has just moved into the area.
The wild hills of the west harbor monstrosities, horrors and great riches for the bold.
Main Theme:
Revolution! Androids conspire against their makers. Peasants conspire against their masters. The British, revealed as the masters of Talon Company, attempt to retake America. Gangs conspire against everyone. Some will live, some will lose.
It's the birthplace of the American revolution and the setting, art direction and theme reflects this. Think small towns, Lovecraftian weirdness (NO supernatural!), darkness, mist, rain.
Factions:
The Commonwealth:
A scientific think tank far ahead of the prewar era in some areas of technology (robotics, weaponry, physics) but lacking in others (agriculture, animal husbandry, etc). It exists by using fear of it's android slaves against the locals. Actual population: old and dwindling.
Some bright lights in nearby settlements are culled to provide new talent but the requirements are tough.
Certain individuals plot to end the tyranny; others will do anything to preserve the status quo.
Some of the newer androids have begun to question the way things are, as well.
The Invaders:
Tenpenny was an advance scout for an invasion. Talon were native mercenaries hired to maintain unrest. Now the architects have arrived: An invasion fleet led by the King of England. They are well armed and equipped, but are now trapped on the coast.
Raider Gangs:
Three or four raider gangs vie for territory. Some have redeeming features; others are crazed berserkers. One gang, comprised of all sorts of renegade robots, is led by escaped androids. One models itself after the colonial minutemen. All are potential enemies or allies.
Peasants:
Many are sick and tired of Commonwealth rule. Some want freedom; others just want what the Commonwealth has. Others convincingly argue that they are relatively well off.
The ???:
Something is occurring, has been for years. The peasants call them ghosts, the Commonwealth has no public opinion. But invisible invaders prey upon all the inhabitants of the area. They seem to come from the western hills.
The Player Character:
For maximum replay value, I'd like to see multiple beginnings.
You can choose a character who:
1) Is woken from cryogenic sleep, after experiencing the war firsthand
2) Is a shipwrecked British sailor, cut off from the remnants of the British invasion fleet
3) Is a member of a tribe who has just moved into the area and begun scavenging the virgin wasteland, or
4) Is a disaffected member of the Commonwealth, escaping a forced brain transplant
The four strands would converge, more or less, but the player must choose his true allegiance through the course of the game. There's also the tricky question of whether he is actually human or android (which would be determined by the player's actions, adding more variety as certain perks and skills will open according to the player's choices.)
Retaining multiple outcomes; the player can seize control for himself, overthrow the Commonwealth Institute, preserve the Institute, etc.
At least 2 radio stations; a classical station from the Commonwealth, with periodic propaganda & a 50's rock and roll station broadcasting from somewhere off the coast.
A racetrack you can race on, with a fleet of vehicles that may have an impact on the ending.
This is all daydreaming, of course.