Well, I sort of see stealth actions as a mechanic directly proportioned to the actions of the forces involved. While yes, it is easier for a group of individual scale units to hide and move stealthily than it is for a group of village scale units, it is also more likely that if a village scale unit is scouring the area in search of hidden forces that they will find them as opposed to a group of individual scale units taking the same action.
I see the rules for any other conflict working perfectly well when incorporating non-divine stealth and non-divine detection methods. I consider stealth a function of Body and detection a function of Mind. Although if a reason is given why Stealth should be considered a mental discipline, like say hiding tracks or assembling make-shift camouflage, I might entertain the thought of allowing it.
Recently I had a player with a priest exploring near the edge of a watering hole infested with "large ambush predators" (crocodiles for lack of a better description), and I told her to make a Mind check for her units. It was a household scale unit consisting of of 3 Mind d8 units and 3 Body D8 units. Half the number rounded up were D8 mind, so a D8 Mind at household scale rolled the check. The Ambush Predators had Body d8+2, acted as household units, and there were two of them in the vicinity.
Two household units hiding versus one household unit detecting. In this instance it was more a case of numbers than it was a case of size. The humans saw one, but not the other. Still she had the humans leave the area. Thus beginning a pursuit conflict with the one they didn't see as it attacked from hiding.
One of her individual priests didn't escape the monsters, Ralph. He got eaten. She immediately made an illusion of herself appear and proceeded to force the monster to give birth to the priest it just ate, sending it into convulsions and leaving Ralph with a nice ridged forehead resembling gator scales. Fun scenario. Very creative. Even though she lost the conflict, she won the fight... At the time I didn't think she earned belief from that, but on review of the scenario, I believe she did. I'll have to have her roll for it when we meet again on Friday night.