It's a 14 year old game at this point, but I enjoyed "Tom Clancy's EndWar". It's meant to be played with a gamepad, so it doesn't have much micromanaging. There can be at most 24 "units" on the map at any given time, 12 per side. Multiplayer splits divides the unit count equally among members of the team. Each unit is comprised of a bunch of smaller units (vehicle units are 4 vehicles, infantry units are 4 groups of 5 soldiers, etc.), but you control all of them as a single unit.