OK, I agree with DH that player control must be maintained to a fairly high degree, but should NEVER be absolute! There should always be a certain 'Wildcard' element in whether or not a civil war or rebellion should occur. One possible wild card could be keeping actual happiness levels secret, and instead simply describing citizens' mood using a simply adjective-like content, happy, ecstatic or very angry, defiant, rebellious. Each of these moods would relate to a specific happiness range (like 0-10%, 45-55% etc), but you won't know EXACTLY where within that range your people currently are (unless you are a MM FREAK who checks ALL of his cities every single turn
!)
Another thing I would like to see is splitting the concept of 'civil disorder' into different types-namely 'revolt/rebellion', 'religious schism' and 'civil war'.
1) A revolt/rebellion occurs when a particular 'faction' of your society becomes especially unhappy. Whether a faction can and will revolt would depend on a combination of that factions happiness level AND current influence. If you enter the 'danger zone' for a revolt, your domestic advisor will warn you and even give you a hint at what the faction is demanding.
The nature of a revolt, when it occurs, would depend on the faction behind it. So a workers revolt might lead to a huge loss of shields, a mlitary revolt might cause you to lose control of many of your units and loss of military production and a religious revolt might lead to you losing much of the happiness and culture created from your religious buildings. Also, if a revolt continues unabated, cities containing a high % of the rebelling faction have a chance of units and buildings being damaged. Eventually, cities dominated by the faction might break away in a civil war (see (3) below). You can prevent or put down a revolt by either acquiescing to their demands (via government change, social engineering change or building of units and/or buildings etc) or by cracking down on them hard-via Military Police or social engineering adjustments. The latter course, if not done right, may have the opposite effect, however, or merely create a 'band-aid' solution. Lastly, a general rebellion can ensue if average happiness drops below a certain critical level. The effect of this would be much like the anarchy period which currently ensues when you change government in civ3.
2) Religious schisms occur when a city containing a large number of people from a foreign religion ecclesiastically break away from your nation. Though you retain some control over the city, any religious buildings you have there cease to produce happiness and/or religious culture for you. In addition, rival civs from the foreign religion may build their religious buildings in that city. Lastly, a religious schism increases the likelihood of that city 'breaking away' at a later date (again, see (3) below).
3) Civil War is when one or more cities break away from your empire. Certain critical events can act as 'POTENTIAL' triggers for a civil war, which are:
(a) happiness dropping below a critical level.
(b) Crime/corruption rising above a critical level.
(c) The ratio of Foreign:Native culture rising too high.
(d) Loss of your capital.
(e) A rebellion/revolt.
(f) A religious schism.
(g) foreign propaganda.
(h) changing government.
If a trigger event occurs, you will be warned by your domestic advisor of potential trouble. Any time after the trigger event, however, your city(s) can break away. The chance of this actually happening would be based on:
(a) the city's happiness levels.
(b) its corruption/crime levels.
(c) the city's distance from the capital.
(d) the # and strength of all units in that city.
(e) proximity to another secessionist city.
(f) # of foreign nationals in your city.
(g) ratio of foriegn:native culture.
(h) If the city is already in revolt and/or religious schism.
If a single city breaks away, it will usually join up with a neighbouring power (either minor or major), wheras if a collection of cities all break away at once, then they will usually band together as a new nation (again, either minor and major).
As you can see in all of the three examples I have cited, the chance of civil disorder is NEVER completely random-instead being based on 'pseudo' predictable algorithms. A small, well-run and content nation-state will almost certainly NEVER suffer from civil disorder, wheras large sprawling empires which rule through fear and conquest will almost CERTAINLY suffer a civil war at some point in their lifetime. Of course, there is a very small, random element in this, but the majority of it is decided by in-game player actions (either of the nation itself or one of its rivals). The thing is that these examples, along with other 'pseudo-random' events, would go a VERY long way to preventing the current 'snowballing' phenomenon which is endemic in the game!
Yours,
Aussie_Lurker.