Something I’d like is to set “personalities” for groups when fighting, such as “defensive” or “aggressive”. Based on the style chosen, units would have different chances for blocking a hit or attacking more frequently (but more likely to be hit, due to carelessness). These two examples could be used as such:
Defensive–Hold out until reinforcements arrive! A swarm of enemies rushes a soldier away from your other troops. There’s too many to attempt fighting back safely, so just hold back until everyone else comes!
Aggressive–Push back the horde! A mass of weaker enemies is threatening to overtake your units. Since their attacks do little damage and they can’t take much of a hit individually, instructing your soldiers to not hold back will dispatch them faster, before they can start dealing some serious injuries!