Having read over the game thread in question last night, I'd say -- especially for a heavily themed Merc game -- you're on the right track. Some of your requirements feel a little strange (listing what people "should be able to do" instead of just giving them hard numbers to go by, IE a "minimum die pool for firing Automatics" or whatever)...but they're all in keeping with the theme of the game, even if they're presented a little oddly.
Even for a game with a clear "feel" in mind, though, remember to listen to the occasional "outside the box" player. A dedicated cogs-in-the-machine paramilitary game might be a lot of fun, and having everyone display a general competence at soldier stuff certainly makes sense -- but don't forget the possibility of someone not fitting the mold. They figured out ways to throw geeky scientists in alongside the soldiers in Stargate, right? A civilian consultant (Ellen Ripley) went along with the Colonial Marines in Aliens, too. Corporal Upham, the translator, didn't git in too well with Captain Miller and the rest of the Rangers in Saving Private Ryan, either.
If someone's heart is really, really, set on a weenie that doesn't fit the merc image, ask yourself if you can't fit them in somehow, still. It might mean they miss the first few scenes of the adventure, it might mean adding in some MacGuffin of a plot hook later on (the data terminal that needs to be hacked by the civilian Matrix consultant that set up security in the first place, the magical artifact that needs a PhD in Thaumaturgical Archaeology to take a look at it instead of a merc combat mage, the tribe out in the middle of nowhere that's so small their dialect isn't covered by linguasofts so you need an anthropologist along to get information from them about the crashed satellite)...if someone's just got to play something besides a die-hard merc, if you want to, there's probably a way to cram 'em into the game.
