This has some good potential.
I recommend fleshing out the story of the world war from a global/political perspective well before you start as part of your planning, even if you don't plan to focus on it (because chances are, it's going to be mentioned at least in passing, and you want consistency.) Also, the army character unfortunately has the risk of becoming a two-dimensional "Yes sir" man. If you instill some kind of brilliance but also a streak of rebellion, or a moral code that he refuses to violate, or just anything to make the character interesting, you have a good story on your hands.