I don't feel it would really affect game balance to much to let each player swap out a class skill for a cross-class one to reflect the specialty training given by the military. That way you coulf have your Medic/Comm Specialist/Whatever without worrying about relying so much on NPC's.
I haven't picked up the book yet, but I think I will. Seems pretty cool, and I appreciate the minis from the tactical game.