Well, the example OP gave was a city with no defenders, which can also happen in Civ. But yes, early defenses are pretty weak, especially against a sovereign. There was a thread about how effective a sovereign rush is on a small map.

If the attacking force is weak, a defenseless city should be able to have the population rise up. It's kind of odd that 500 people can be conqurered by one guy with a pointy stick.

i think this would be neat especially if the militia were a certain percentage of your total population.  then assuming they won, after the battle you lost a certain amount of population based on the loses incurred in the battle.

say you have a pop of 1000(not sure what city level this is) then you might have 10 percent of your pop in a militia.  this would be 100.  i say make 5 20 unit stacks for combat.  loose a stack and your pop drops 20 people after the battle.

edit: this would make a really cool tech advance in the warfare tech. it could get a little better with a couple upgrades. maybe go up the amount of population that can be in a battle.  perhaps 1st level is 10% then second could be 15.  max out at whatever you think is balanced.

I would suggest that one thing that would help is simply not to call the most basic unit a "peasant" because then people ask..."How can one peasant hold 30 peasants captive?". If you call him a "thug" or something, then at least it makes some sense that he might be able to intimidate some peace loving towns folk into doing his bidding.

You could argue that whether or not a city is conquerable by a guy with a pointy stick is possibly as much to do with alliegance to a sovereign than anything else. It's possibly a bit late to add new concepts such as cultural alliegance, but maybe having militia power being improved by the sovereigns charisma might make sense, and make Cha not the usual dump stat. A charming sovereign commands the devotion of his or her people, making it harder to take their cities without a fight.

One of the city upgrade options is currently "Spawn Random Guardian Unit". If you did add militia, this could be "upgrade militia" option instead. So a basic city starts with a fairly useless militia unit by default, but choosing the upgrade milita option each time the city grows would mean you would maintain pretty powerful garrison there, large enough to defend against moderate armies without a large expense. This would be pretty useful to border towns, and add some decision making and variety to cities, as you would have to chose this over gildar or tech production.

+1 on the militia being an upgrade. But even without the upgrade there should be some defense from the city.

For instance with no tech involved, each time a city is attacked the gam ewould spawn some peasants and one or two sergeant.

A simple formulae like every 50 pop would get you a chance to have a militia and every 200 pop would get you a chance to get a sergeant.

A tech would replace militia by hardened battlers and sergeants by captains.

A city upgrade would change the numbers : a peasant for every 40 pop.

So a city with 200 pop would get 1D4 peasants to defend and 1D1 sergeant.

With the upgrade you get 1D5 peasants and 1D1 sergeant.

A watchtower would have some defenders with it. If you choose the upgrade for your city the soldiers are better trained.

The problem is more pronounced than just needing population to fight as very weak militia.  [Though, that's a good idea.  See Empire:Total War for a nice example of implementing this.]

It needs to be harder to attack a city than it is to fight the enemy in the field, so that a weaker army can retreat to the safety of a city, while the stronger army pillages the countryside.
Think of how this happens in HOMM with the castle defenses and arrow-towers. 

This doesn't happen without fortification tech and an expensive and VERY long build-time building, and even then the bonus is minimal.

How about an arrow tower building, that acts as an archer (and scales up over time as you get parties, squads, etc.).

Or have on-map tactical features that provide cover vs ranged attacks and a defensive bonus for city defenders.

It already is. Cities provide defensive bonuses.

Great idea! To tie it all together, you could use Charisma to determine those numbers (50 might go to 30 if you're a high charisma leader, showing that more people are willing to fight for you).

In addition to making it more realistic and less bizarre, militia defended cities will make the steamroller strategy much harder. A very dominating army will then be weakened by each city conquered and can't continue conquering indefinately.

Complicating the steamroller strategy is a good design choice I think.

A good example is GalCiv II where planets are conquered by population from your own planets and usually a lot of people on both sides die. Such mechanics make it impossible to grow too fast by conquering.

Great idea!

Some great ideas here! I've got a few ideas, I'm pretty sure some of them are beyond what is going to be in the game, but I thought I'd share anyway.

There could be a faction trait that makes a larger percentage of the population take up arms when attacked, called 'strongly patriotic' or something. Same thing could be done for the sovereign, give him a talent like 'inspiring' that has a similar effect. Factions could also be 'militaristic', meaning more people have had some military training, giving better troops, and due to civilians owning weapons, stronger militia units. Ultimately, a militaristic, strongly patriotic, egalitarian faction led by an inspiring sovereign with high charisma would have a good advantage defending towns by spawning a larger, stronger militia when attacked.

There is no city morale or happinessmechanic in the game, and I don't think the dev's are planning on including it ATM, but it could have some nice effects if it was. A city with high morale would spawn more militia, and one with low morale less. So a strategic map spell that alters a city's morale would have an effect on combat.

The spawning of militia could depend on the strength and perceived intentions of the attacker. So if a necromancers undead horde attacks, intending to turn everyone into a zombie, the militia would fight. If there are no defensive units in the city, and a large enemy army of the same race attacks it, maybe the city just surrenders, hoping to only be occupied. Off course, if the city is then sacked the next town might put up more of a fight. And if an occupied city is attacked by a liberation force, maybe some militia are created inside the walls, hoping to drive off the occupying force.

Like I said, most of these things probably won't make it into the game, but maybe in an update/expansion/mod some day...

Agree that the AOW2 model was a good one.  But those defenses were far cheaper and easier to access than they currently are in EOW2, and ranged units were also more accessible - everyone could build some basic archers right from the beginning.

Erm, yes they did. The rising of the North against William, the Great Rising of 1381, the Peasant's War of 1525, the Maid of Orleans herself. And those are just peasant uprisings, there's numerous occasions when Lords rebelled against a conqueror or their rightful monarch with the aid of their peasantry. The thing about the feudal system is that allegiance was to individuals rather than a concept of nation or country, seizing the land was only half the battle, you also had to come up with a "right" to rule in order to secure the loyalty of those who lived there (although often it was simply a case of making a generous donation to the church to get the local clergy to declare divine favour.)

I think instant razing is a mistake.  I'd really prefer something like the Civ5 system, in which cities being razed reduce 1 pop per turn until the city is gone.

Maybe: city loses 20% of its population per turn and one building at random, so it takes 5 turns until the city is gone completely.

Something that lets a defender retake a city rather than having it instantly annihilated.