All your units are individuals and each named completely at random and have individual unit stats and personalities. Their graphical appearance is different, as in they all have completely randomly generated build, face, skin tones... individually battle scarred clothing, armour that gets marked as it gets attacked. Infinitely persistant dead bodies/weaponry/vehicles... and vehicles leave infinite tracks on the ground. True veterancy, units become better based on training and experience on the field, grow sluggish if left to eat donuts and camp all day. Units can recieve promotions, commendations. Additional resarched weaponry gets dispatched properly over time, so air drops and stealing enemy weapon caches. The environment has a real effect on an army's abilities, their momentum, accuracy, morale (proper random character morale, not bonus based. As in a recriut who is naturally hard as nails will have good morale, a weaker one might be intimidated by rain etc... Not necessarily affected by rank) Basically get it as close to being realistic as possible.