What if as soon as our units enter & every turn within the zone of control of wildlands, there was a certain percentage chance to:  Lets say your moving through a desert, you might lose a member of each army group you have to some giant ant lions - giant insects that make a cone in the sand & sit buried at the bottom waiting for an ant or anything of similar size to fall in, once they fall the creature throws up sand like a fast shovel trying to make the victim trip & drop to the bottom where it's snagged & dragged under

or upon entering a forested wildland you had a chance to be met by a friendly fairy that gives you some magical berries that do such & such, or lose some troops to a lycanthropy ambush/outbreak

Perhaps we could have a Wildland that had events like this, Upon entering the ancient burial grounds of the so & so your forces slowly dwindle due to a plague of sorts & repeated attacks by what are believed to be vampires during camp, the troops lost would be added to the Necromancer's/Liches army which would be unleashed upon whomever wonders too close to his crypt or would unleash upon the closest cities once his army had grown to an adequate size, maybe one could have a chance of finding a Lost relic that the Nec/Lich would be willing to give you he & his army's servitude in order to obtian

Just thought I'd see if this kind of thing sounded any good