Historically, wealthier cities had wealthier citizens, who could afford better armor and weapons when their services were required.  You can generally expect that citizens of a war torn world in a wealthy city would be able to afford better arms than those in a destitute one.  Also, if a city is a crossroad or manufacturing hub of a military resources, it stands to reason that many of them will end up in the hands of private citizens.  I'm not suggesting by any stretch that militia should be as well equipped as units that you could otherwise raise as professionals (and no where near as well trained), but that doesn't mean that they should all be pitch fork armed peasants either.  Perhaps some few militia in metropolitan cities might even be armored, horse riding, inexperienced but impeteous nobles?   

Also, Civilization does not have militia units as I described.  In the original Civ, they were standing army units that remained permanently and required persistent upkeep even though they were called militia.  The only game in recent memory where I have seen them appear in this fashion is in Empire: Total War (too bad the game is virtually unplayable in the grand campaign.)  Most strategy games have improperly represented the concept of a militia, even if they have labeled units levies, town watch, or militias.  

The point is for them to be present only when it's necessary for them to defend.  Real world militias never stood assembled at the city gates 24 hours a day, 30 days a month, all year round, never tending to their fields or professions.  I'm assuming that raising soldiers will consume population, so simply relegating the militia unit to a kind of raisable soldier wouldn't work because it would take population away from your city, which really defeats the true purpose of militias.  Also, if militias are simply standard units, than you can technically field them in far off lands, which explicitly defeats the purpose of militia units to begin with.  I don't see how my idea would be hard to implement at all, either.  Simple have an algorithm for what militia will rise to fight when under attack, and have a little icon somewhere in the city interface that tells you the militia level in number and calibur. 

If there is any further confusion as to what a militia is meant to be, refer to: http://en.wikipedia.org/wiki/Militia

As an aside, the French have fought courageously, and died in great numbers, in every war that they've ever been involved in.

Yeah, I agree that defensive conscripts make more sense than offensive ones, but rather than perhaps making offensive conscripts non-present in the game, they can simply be made much less viable by virtue of the fact that penalties would stack the longer they are gone.  Peasants conscripted quickly to a defensive war can return home quickly.  Those on prolonged campaigns in distant lands would cause exceptional unrest and productivity penalties abroad. 

And the difference with conscripts and levies/militias is that the levies never even have to leave their farms to begin with.  They just rally in defense of their city, and meld right back into the population as soon as the fighting is over.

I like the general ideas here very much, although I might have called it all 'militias' and just had separate effects for whether they were automatically invoked by an attack on their homes or they were called to arms by their leige.

On the wealth point, I think Demiansky is onto something--the classical Greek definition of citizenship depended on being rich enough to provide your own arms and armor for when you were called to battle. It was the rich moms who told sons to "Come home with your shield, or on it." For Elemental, maybe this 'wealth' could be a byproduct of upgrades for the regulars. I don't think I've spotted the devs say anything specific so far about what happens to obsolete gear when a regular unit gets an upgrade. Maybe the old stuff goes home to Cousin Ted so he can join the miliita?

It also seems like drastically reduced production and possible morale declines could be effective organic limits on using militias for offense. Help take a nearby enemy town? Sure, why not. Go traipsing off to a faraway land for a year? Maybe not so much.

I like this idea a lot! Hope, it makes it into the game!

Thanks for all the input guys.  Let's hope a dev is watching somewhere