Just how feasable (or likeable) would these moddings be?

[TheBladeRoden]

I'm new in the Civ universe so I don't know if these things would work.

1.A UN-like system where membership is either voluntary or perhaps as a result of culture spread. There could be votes for a defence pact between all members, and trade benefits. But another difference is that members vote on adopting the civics of whatever the Secretary General has, not just the fifth ones.

2.Building units costs coin and hammer, making a three-way balance of emphasizing production, research, or culture.

3.Rioting cities can go neutral rather than automatically flipping to the neighbouring country's team.

4.The influence of a government system can spread like religion or perhaps like a city's ethnic population
[----74% Communist---/-------]

5.Natural Distasters
You may think you're save from that other guy's army, but no one's safe from the random hand of fate. Stuff like meteors, storms, or infectious plagues.

6.Weird victory conditions like having to reduce the world population to a certain level, or bringing down the health levels or commerce infrastructure of the other empires.

7.Will we be able to import models and animations for leaderheads?

 

[Jon Shafer]

Possible? Certainly. Some things with more difficulty than others. Though, the AI is another matter... teaching it how to use such concepts without making the game ridiculously easy is no simple task.

I'm not quite what you mean by "cities go neutral" though. Every city has to have an owner. You can certainly make a city Barbarian, but I'm not sure that's quite the effect you're going for.