What a great idea
The basic concept of having spreading population points and (for the most part) uncontrolled migration and cities emerging is truely inspirational it would add an aspect of uncertainty to the game
The ability of the population of a city to construct buildings is great however could i possibly suggest an improvement:
I find having alot of buildings is distracting (and often annoying) for the Civ4 Warhammer i suggested a slightly different system to building individual buildings
This system involved having quarters or areas, which would work like conventional buildings but following zonings
Financial Quarters: Would consist of banks, commerical and light industrial/manafacturing buildings (it at lets say at lvl 1 grant a +25% income, +5% shield production, lower inflation, greater chance of a Rhye's style depression which with the discovery of tech x could change into a great depression) this could under condition of discovery of tech y change it into a level 2 quarter (which might grant a +50% income, +10% shield production and +5% science, but cause higher inflation and have a much larger chance of causing a depression) but this change could also occur semi-randomly, whereby the citizens of the city accure the financial know how devolp better facilities and improve efficency/access to capital etc (so after x amount of turns or whatever forumla the quarter turns into a lvl 2) and this could continue into lvl 3-whatever
Industrial Quarters: Would follow much the same but would instead consist of light and heavy industry and would give greater shield bonuses, but increase the chance of disease etc
Other types of quarters could be Residental (although in a city i would imagine this is implied, however you could have suburban residental quarters and inner city residental quarters etc)
Religous Quarters which would do whatever the prevailing wisdom of the situation is (i would go for a small +science and a small +cash as well as more happiness (but with a drawback, if the city is religously divided disafected religious group is less happy etc)
Civil/Goverment (probably increase corruption, increase income, decrease unhappyness) etc
Farming (wouldnt be sure aobut this)
Certain civics would bias the cities towards buidling this or that, religously absorbed civ would lavish massive amounts of private capital (monastries/catherdrals/churches/parishes etc in the early middle ages tended to be built with sizable portions of the donations coming from the nobility, but surprisingly enough peasants donated very heavily to build them as well), capitalist secular states might only devote a smaller % of income to religous buidlings although that smaller % might be larger considering that they would be making a greater sum of money per person) etc
You would limit the amount of quaters to a population style thing, with a population of 1 limiting it to 3 and expanding to whatever you wish it to
This might make it significantly easier to code to your civic style restrictions... a controlled civ would be able to control what it builds and what stuff it can control much easier a religous state would be able to control all the religous quarters and bar religous minorities from using "their" churches etc
Quarters could be further specialised by limiting a quarter to 1 upgrade Financial quarters could have for instance a Media Upgrade (more culture etc), an early upgrade would be a Farmers Market/Country Faire etc)
But any which way this would be even further hands off for the player
those civ gamers with an authoritarian streak would play with authoritarian civics... otherwise they couldnt control a great deal, past national defence and diplomacy
I see civ as basically flawed because the player has to much control, civilizations are not something you can order around and bend to your whims they tend to be made up of large amounts of different peoples who hold different views and beliefs (which i think this mod will do nicely to adress)
As an aside would it be possible for the Houses to transmutate into democratic parties (which would i think end up with some entertaining possibilities, "Why is my super industrialised state ruled by the agrian party?" which is in line with the slightly random qualities of the world)
But other wise a great setup for a mod
(PS: I would be happy to offer whatever help i can)
Proper Laizez Faire Capitalism here i come
