Exactly. Someone who couldn't manage a pullup is sure as hell not going to be in any army that actually does, you know, fighting. And if they were, they wouldn't last very long, if nothing else machine guns weigh a ****ing ton after about the second hour of carrying 'em.
And you know what? Iraq'snot just hot, it's ****ing hot. When they're not in a combat situation or likely to be any time soon, light uniforms really are necessary- heatstroke would be decimating the forces otherwise. But anyone who's going to be fighting is going to need to move around a lot in some pretty rough terrain. You ever notice how when you scrape your elbows even a bit your arm gets stiffened up? Yeah, that's you dead in a firefight, right there. Good, thick fabric like is used in military clothing isn't just there because it makes the soldiers look bigger- preventing relatively minor abrasions and lacerations helps prevent rather more critical things like a 7.62 round to the forehead. And that's kinda important. Spare clothing is a good tradeoff when you're in an excessively hot climate. And given the heaviness of the rest of that suit, it wouldn't help much in such a situation there anyway.
You don't like unbelievably over-buff characters. And that's fine, I'd be cracking steroid jokes right now if you were. But are unbelievably stringy, frail characters any better? Hell, maybe it's just me, but that sounds a good bit sillier.
I think you're making the mistake of assuming "looking funky" is a desirable trait in military gear. It's not, if you're designing it around aesthetics and fashion it's gonna just look wrong, wrong, wrong, no matter what you do. There are very few things more utilitarian than the army, and if you're thinking about something other than what is needed for those clothes/vehicles/whatever, you've already ****ed up. Just having some exteraneous for no clearly stated reason, or making up half-assed excuses after the fact to defend the thing, isn't gonna help- you're not gonna convince anybody, and people will notice.