If your unit is getting smashed to the point of routing, it is in serious trouble. To answer your question, yes I have had units perform poorly in combat and lose valour, although this is rare. Analyze your enemies’ forces and know which unit match-ups are to your advantage. Yas Terazawa’s unit comparison tool has helped me a lot. Having a unit hold the line while other units maneuver is a necessary evil. Asking the impossible of a unit isn’t.