Here is my idea for wound system in the game. I'm warning you, my English is not so good and things I want to say are a bit complicated.
1
Everything deals random damage. Of course not flat random, but something like normal/Gaussian distribution.
I don't know, maybe it is already in the game.
2
If HP drops to 0 character is unconscious or dying (same effect for the game mechanics). He just lies and can't do nothing, even can't observe the area. Or even if he can, he can't talk, so others soldiers can't see what he sees, so for the game mechanics he can't see.
I really want more unconscious in battles.
3
If HP drops below -1/2*maxHP character is dead.
Even dead he still should be visible on the soldier list. I hate when I lose a soldier and I don't know or don't remember which one because he is simply evaporated.
4
When character takes single damage (from weapon etc. not from bleeding) there is a chance for taking a wound.
An example formula:
(after taking damage from every single bullet)
damage/maxHP*maxHP/currentHP
Three things should count: power of damage (it's obvious), maxHP (bigger is less vulnerable) and current HP (because minor wounds, not taken into account by the game mechanics, can become a "real" wound).
I don't know how damages from explosives weapon should exactly work. It would be good if from one explosing character can take more than one wound.
5
Type of wounds:
Location - random, let's say: 15% head, 30% torso, 25% legs, 15% right arm, 15% left arm.
Wounds can be: Light or serious (random). Serious = bleeding, character is loosing some random HP each turn.
Effect from location (examples):
Legs - Light: move cost is double. Serious: character can only crouch, move cost is quadruple.
Head - Light: some penatly to overall accuracy, maybe some chance for stun effect (but I don't know nothing about stun in this game). Serious: same but more, maybe automatic stun or unconscious.
Torso - Light/Serious: character loses some amount of TUs.
L/R Arm - Light: using items and weapon costs more TUs, for weapon less accuracy, for items less effect (for example med kit). Serious: character can't use this hand at all.
Edit:
Medkit - stopping bleeding (x% chances for use).
Drugs - adds some temporary HP (only one effect per battle).
After battle - best medic in team automatically tries to stop bleeding (from most wounded soldiers to least) with bonus for not battle situation and for super medkits in the dropship. Or just blooding is automatically stopped after battle.
Hospitals in bases - heals HP (relatively fast) and makes wounds disappearing (serious to light and light to none). Wounds are healing slower than HP.