I actually like that idea as a penalty for handling wounded team members.
If a team member gets wounded and you leave him out to die, the AI "morale" will degrade.
Actually, any death will degrade AI morale. It can probably be worse if you ignore a wounded teammember and don't do anything to help him (dress the wounds or something), as opposed to someone dying immediately as a consequence of a clean head shot or something.
As for morale degradation: AI will have less precision in aiming, slower in obeying orders, will take cover and take less risks and pay less attention to surroundings (they are worried and distracted by the loss of a team member of course), thus they will be less aggressive and more vulnerable to enemies flanking them.
And this can carry over as you roll into new missions.
So, making sure you come home with everyone you started out with, should be a high priority because if you don't, you'll lose your AI team effectiveness.
On the flipside, always finishing a mission with everyone still alive means having a team that is more and more responsive and effective and aggressive since will they have more confidence in you as a leader.
Losing a soldier due to wounds would affect team "morale" less negatively than death (of course) and getting replacements for KIA team members would also degrade AI performance since replacements would not be as well integrated with the rest of the team.
Just my 2c.
PS: hello everyone.