Not sure if this was already recommended, but I didn't see it on the comprehensible suggestion list, so I'm going to assume 'no'.
The Glade Runner, a start-level Elven unit in Age of Wonders II, was designed for skirmish combat. Due to the game mechanics, he failed horribly and was little more than a decent scout.
I've been thinking...why is it that the only battles that seem important involve 10,000 vs. 10,000? Guerilla warfare and brief skirmishes, to harass enemies, have been forms of tactics for a long, long time. One nation gets taken over by a vastle superior one (militarily speaking) and, although they have lost a number of cities and their own grand army has been scattered, they fight back with small groups, harassing key points and making it so the enemy never rests.
If nothing else, the ability to concoct these sort of strategies ought be an option. Skirmishes would impact the morale of both sides - you can never rest, as you're constantly on the lookout for attacks - and guerilla warfare would use small numbers in a strike team to try and optimize damage. Not only a subtle way to fight, but a brutally effective one, especially if spells of invisibility and concealment become an option. It will require thought to properly initiate, but could be even a sort of game or a unique combat mode. Say, give an overland army a 'skirmish' mode button. When in such a mode, they move slower and have concealment in rough terrain - heavily forested areas, deserts, mountain ranges, etc. Such a mode can be used only be very small armies.
When attacking, then, you don't just initiate tactical or automatic combat. Instead, you are given the option to engage in a brief skirmish (a timed tactical) or guerilla warfare. For guerilla warfare, your small band of soldiers appears on a battlefield at, say, night, with the enemy camped out ahead. What happens then is up to you...but begin with the soldiers caught unawares, have some sentry soldiers patrolling, etc. To be caught ends up having the alarm raised, and an angry army facing your small band.
