To lighten the micro management load create natural hierarchies. Add charisma and intelligence to your units tab off variables, intelligence enabling a unit to move from soldier to a commander and charisma to inspire troops to follow. You can either add a rank structure which the player issues or make it experience based or ideally both.
For example you send a rabble of units to take down a monster, a good chunk of the group dies however a few survive. These warriors earn rank for winning the kill and now when ever you issue an order to these new higher rank units they will grab a few soldiers and bring them along and issue specific skill orders (caster skills) to those units (so you don't have to micro them). The higher the rank the more units, teams or groups of units they will use to achieve the action requested of them. Now your surviving commanders are sent to kill a monster and each bring teams along with them. That same monster is killed easier, not because of more troops, but because of a truly better military.
This system could be carried across to none military as well. Think of a wood cutter becoming a lumber camp. A smith becoming a forge. Etc. This doesn't happen because you simple clicked it into existence. This happened because your populace has a wood cutter that is intelligent and charismatic enough to lead other wood cutters. This system could explore taught skills as well, but I digress.