Solid ideas that allow for interesting depth to game play for the npc factions..

i think that based on the city level you should have a sort of militia unit if there are no defenders.  it seems to me that if a wolf attacked your town of 2000 somebody would try to step up and take it out. a unit should be created with 10 percent of your cities max population for that level.  so a city of 2000 should have 1 unit of 200 or maybe 5 units of 20. something like that. also if the militia unit is defeated that amount of people is removed from the city. if they are attacked and win but still incur loses that should also be represented.

also based on a creatures intelligence the city should be razed.  if an animal attacks its not going to start tearing down buildings. its just gonna kill some people.

1 int = kill a certain amount of population.

2-5 int = take out a random tile.

6-10 int = target something specific

you get the point.

I agree. Wild animals like wolves may kill your peasants while giants could smash buildings down. I don't see how wolves can destroy my outpost????? Nonsense

Alpha Centauri did something similar for mindworms - they ate population instead of taking "control" of the base.  It's a solid idea and definitely deserves a good looking at.