the more i think about this, the more i think it should be a Sengoku Mod.
youre rebuilding a country, so the victory by becoming single ruler is there. its much more about war and chaos and conflict then CK is and its about a country which has fallen into warring pieces.
the titles could all be military ones, the clans or whatever i cant get my head round the jap words to make heads or tails of the sengoku tiers, could each be a different shard of a shattered US army each lead by its own claimant to the presidency and you win when you control enough land to be one and only president.
Set it maybe sixty or eighty years after an event only vaguely hinted at that was serious enough to necessitate placing the country under emergency military control and annexing alot of land into military hands to provide and sustain the army doing its vital live or die work. and long enough that by the time it was over a generation had past so the people in power had never known any other way of living. And then have the game start with the president [of a military junta] and his direct line of succession being killed off or discredited and plunging the place into civil war with the army leadership breaking up into dozens of pieces each making attempting to place their own man in washington and then the game start would be after the dust has settled on the first chaotic many-couped conflict with the map broken up between a dozen or generals all claiming to be the one legitimate US army and ready to spend a generation or two battling each other for the crown.
CK would need a mod set during a time of stable civilisation, maybe not stable politics but where the ruling class is unchallenged and things more or less stay the same, whereas the whole point of sengoku is its set during a time of chaos, which is what a post-apocolyptic mod would have to be. and it comes out first anyway and its more about war too.
Not that there couldnt be a CK one too. but itd be better along the lines of a Canticle for Lebowitz setting, for a grounded in now one i think Sengoku would be alot better.
EDIT; i just scribbed up a backstory, its rubbish but it makes the point of how itd suit a military character game like sengoku better than a kingdom character game like CK2, also i saw that it already had the name right there so i had to. the names were taken randomly from the Victoria VIP random leader names. If scenarios can start with characters already hostage and treaties built around that then that would be a brilliant way to start with the most powerful army being made up of mostly alliances held together by holding their leaders hostage from the capture of washington. Ninjas could be the CIA or something.
These Warring States
A Post-Apocalyptic Sengoku Mod
Introduction.
In the chaos that followed the remnants of the government under emergency powers place the nation under matrial law. Military personal were put on in full force, carrying out the evacuations and the emergence civil defense. The land and property of the dead and missing was appropriated into military hands to feed and provide for the army.
The was forty years ago. Back when people still believed the world would recover, very few now remember what it was like before. The death of President Lockwood was taken with suspicion, blame fell on his successor President Rose who was shot within days of taking office and President Arran soon after. By the appointment of President St-Clair the nation was on the brink of chaos and then General McRae seized control in a sudden coup but failed to consolidate power. With all legitimacy lost from washington and no clear line of succession central command collapsed, throughout the nation dozens of presidents declared themselves and went to war against the others. the initial conflicts ended without any victor or even any gains, the generations of war that followed where the broken militaries of the once united states battled over the presidency eventual became known to historians as the Warring States Period.