Each soldier's skills also come into play during missions. Some might be really good at hand-to-hand takedowns, while others will be able to drag unconscious enemies back to the truck faster. And if you send in guys who are wearing the right uniform, they can usually run around unnoticed, which makes things much easier, so long as they act normal.
Camouflage aside, you'll have a much easier time sending Snake into battle with three soldiers to watch his back. You can switch between these guys on the fly, with the inactive characters safely hidden in strategically placed cardboard boxes. Because each character can only carry four items at once, there's a strategic element to it, and you'll get more out of your troops if you equip them with different weapons and gadgets that play to their strengths.