Wait, you snipe Fidel? That's just rude. Yet another reason not to get the game, thanks...
To me, war games make great multiplayer games and. Single player... War can be a good back drop for a story. Just check out any Fire Emblem, ever. But more often than not, the characters either fall into the categories of one-dimensional or trying too hard.
The one-dimensional character is serious business. He makes no jokes. Sometimes, he'll have some companions in the form of equally one-dimensional characters. These usually fall into the following archetypes: The Silent Badass (player character), The Scientist, The Explosives Expert, The Strong Commander, The Sniper. One of them, usually the commander or explosives expert, must be stereotypically black.
The trying-too-hard character is the complete opposite. He'll be an expert in all his fields, a one man killing machine. He'll laugh off his superiors and run into the thick of battle while cracking jokes all along the way. But all he really wants is to get home to his family, whether that be daddy's little girl, ma, honey bunny, or wifey Jane. His companions are only there to be the butt ends of his groan-worthy jokes. Eventually, one of them will die at a point where it was not-at-all-obvious, and Mr. Tries-Too-Hard will have a quiet moment of introspection.
The first Modern Warfare had an alright story but one-dimensional characters. Bad Company 2 had all-right characters but a trying-too-hard story. Looking at the war games I do have, most of them don't even have stories: CS:S, Battlefield 2, Battlefield: Vietnam, BF: 2142, etc.