out of city fatigue

[Syphon520]

would it be possible to decrease the units move spaces then make some sort of mod to give desertion and battle fatique to units not in a city or fort...for instance it take 4 moves to move from 1 city to another so a army containing a general gets X amount of turns outside of walls before it gets fatigue so after X amounts of turns and the army being outside of walls if it attacks or gets attacked it suffers a penalty to moral or somthing equaling a set amount for times out of walls. so a unit outside for 4 turns with a general giving it 2 turns stability would take a penalty of 2 when attacking on turn 4 therefore inploring you to make forts and rest before marching 4 turns and attacking.
I have no idea where to even begin on somthing like this but would be nice to see incorporated somewhere making your armies more like real ones than units that can force march across europe and attack another army at full strength.

Please feel free to post your idea or any help you can add to this idea and maybe we can get somthing working : )

[Mataputas]

The dessertion thing... I don't think that's possible. The fatigue and lose of morale, you can do it, but only for named characters. You can use a script or implement it through traits.