i am not sure if stardock is planning on implementing this, or if they already have and its just a bug that it doesn't work.  when i place a city in a hill i notice that it doesn't give the hills bonus to the guards stationed in the city.  now it may be doing this and i don't see it, but i think that this is not in the game.

so... i propose that cities pass on the terrain bonuses(and negatives as well) to their guards that are stationed there.

this would make placing cities a little more strategic other than just looking for resources to gather.