I am a veteran and a retiree. I take you points. However, what bothers me is this statment:

… Suppose a human could be engineered who slept for the same amount of time as a giraffe (1.9 hours per night). This would lead to an approximately twofold decrease in the casualty rate. An adversary would need an approximately 40 percent increase in the troop level to compensate for this advantage.

You say researching is not the same as endorsing but in my many years in the service I found that what was researched was most often adopted.

It's troubling to me that even a consideration of engineering humans specifically for war is considered. After all, who can object if it reduced casualties? Perhaps the best way to reduce casualties is to think very hard and very clearly before starting a war.