I think you have a good idea, but I'd phrase it differently. Give combat
forces tactical options such as:
column charge, form square, skirmish line, mob, stand fast, phalanx, etc.
Then set up a matrix where each tactic is compared to each other to give an
outcome. For example, form square would be really good against a mob attack,
but lousy against a column charge. If each tactic had its strength and
weaknesses, this would prevent combat from ever being <solved>, but it would
keep the variability in the hands of the players, not the ghod of luck.
(Yes, this is similar to RIMWORLDS.)
Furthermore, certain advanced tactics, such as phalanx, should require
specialized skills (9599: form phalanx) and perhaps require the
participating troops to drill in using them.