Only issue I could really see here is hitboxes. If the female soldiers have a smaller frame and are harder to shoot it kind of ruins it.
Just make them able to carry less and run for shorter distances :p
Oh and of course the inevitable complaints about women characters getting killed online equating to supporting violence against women (you know it will happen don't lie).
True without a doubt also. They will find some way of fitting it in. Even if they have to make custom maps themselves where the (male) player character has to go around stabbing women in a basement.