JarlFrank
I like Thief THIS much
For all its flaws, GenderNonspecificPersonkind(tm) actually proposes an interesting middle ground here by stacking units into groups of 4-8, then having the battle play out on a designated field. It's far from perfect, but allows stacks to cooperate through reinforcements, and deployment of larger stacks an be limited by landscape, line of sight can be a factor, and battles can be fought over more than one turn.
Didn't Call to Power do something similar too?
8 unit stacks that would engage as stacks rather than one on one.
Something like auto-resolved Total War battles or Paradox style battles where it's stack vs stack is much better than the classic Civ 4 doomstack system.
That can take army composition into consideration and you can have formations and shit even without making it too complex.
You can choose a position in the formation for your unit, and it will attack forwards and encounter whatever enemy unit is in front of it. Ranged units can attack from back rows, melee only front. And bam you got a workable combat system.