If anyone’s familiar with X-Com (another great turn based tactical/strategy game), injuries in that game reduce your character’s capabilities due to physical injury and pain; this is also true of the new X-Com per the ‘Red Fog’ optional setting.
Definitely would like to see an equivalent in Battle Brothers, either as a core mechanic (that could be specific to higher difficulties) or an optional setting; it’s a way to make the game more challenging that emphasizes realism/verisimilitude. Though this mechanic would apply to enemies as well, it’s a false symmetry in that you are altogether more affected by your opposition due to your casualties mattering infinitely more, and the increased probability of suffering them that such a change would imply.
As to how this might work mechanically, Health damage beyond 50% of a character’s maximum would result in penalties to all non-Health stats that scale with the amount of damage taken up to say a maximum reduction of 50% to all stats; these penalties might be halved for enemies that don’t feel pain and only suffer loss of effectiveness from actual trauma (such as Undead).