A race where you can only have a certain amount of unique "spawner" units, but where each one can almost instantly summon a temporary army? The commanders would be able to summon units instantly at a typical resource cost, but the units disappear after a while, and the units would probably not necessarily be that powerful and rely on surprise and numbers.
How about a race, probably a nature race, where almost all units can't be directly controlled? You would have buildings that periodically create units, but the units either wander around, patrol your buildings, or look for fights? That would mean you wouldn't have a lot of micro to deal with as well, but you have to focus on what buildings you create and where you place defenses.