I think there should be health bar in those units.
Example:
You have awesome/great/godlike vet 3 AT Gun in position! Crew have 100% HP but gun it self have 5% and you dont know that. 1 shot = loss. I know i can repair it but it would be good to know if i need to do it and back gun to behind line or stay there. I'm sure every one had that situation.
What do you think guys? Is it important for you to?