The biggest problem is the burden this will put on the soldiers. The guys will stop to 'help' the girls, and carry their part of their packs and gear for them, and things will go slower and softer for them, etc. I have seen it.
And if you think there will not be jealousy fights and late nights with rustling in the bushes you are wrong. MPs have caught late night rendezvous in every place you can possibly imagine including inside of garbage dumpsters. These young soldiers both boys and girls are like rabbits. The watch schedule is going to be all messed up. You could always just pick a couple names off the roster and send them out, but now you have to make sure you don't mix men and women together, or this guy, with that girl, or that girl with that girl because they hate each other, and on and on. just a mess.
And, wait until some of these girls get captured. The way the Taliban treat the men is unspeakable, what they would do with female captives is unimaginable.
Oh well. Fortunately it is not my problem anymore.