Make it subtle. That doesn't have to mean it's not flashy, but the flashiness is grounded in a sort of discipline that takes a fair bit of research and careful thought. Don't just say, "This is the guy with the big gun (Gunny McShootface), and this is the martial arts guy, and this guy has a sword", but instead frame it more like, "This guy used to be an MMA fighter before he joined the unit. This other guy is the sole survivor of an ambush that massacred his unit, and he's spent the past year inventing new creative ways to kill the enemy. This third guy follows a mystical meditation practice that everyone thinks is hokey nonsense but then he keeps getting lucky far too often for it to be a coincidence... enemy guns jam, guys trip, his bullets ricochet in just the right way... it's uncanny"
How I would approach it is with this principle:
When someone is first learning a skill, he has to first discipline himself to the orthodoxy of that skill, and put his own ego aside. The master shows the apprentice how it's done, and the apprentice learns how to do it the way the master showed him. But then, once the apprentice has internalized the fundamentals and become a journeyman, he is free to start experimenting. Having mastered the fundamentals gives him the freedom to get creative with his work, and that's where you get innovations in the field and particular styles and signatures that, as a new master, he can pass on to his apprentices.
So with a team of warriors, they all must hold themselves to a certain degree of uniformity with respect to the fundamentals of combat, and even a uniformity of equipment if they are part of a standardized army. But where they can then shine is in transcending the orthodoxy to make moves that a lesser grunt would not be able to pull off. For example, in the story of the 101st Airborne when Lieutenant Speirs ran across the German field of fire without any fear to make contact with I-company on the other side of a building. No other soldier would have had the balls to do that, and because of the sheer audacity of it, the Germans didn't even shoot him.
You can have situations where maybe a guy has the barrel of his rifle grabbed when he's rounding a corner, and he quickdraws a knife to kill the guy: something a less-experienced soldier wouldn't think of doing in the heat of the moment. Or a guy is jumped from behind and pulls off a flawless jiujutsu move to throw the attacker and pin him. I'm talking about the sorts of skills that may never come up in a typical fire fight, but then there's that one unexpected situation where a character might have died if he didn't know how to pull off this crazy move without thinking.
Also remember that artillery and airstrikes and other top weapons systems may dominate open battles, but they can never fully replace the function of boots on the ground. The simple reason for this is that aircraft can't guard street corners. Artillery can't patrol roads. Tanks can't go into buildings to separate hostile combatants from civilians and look for specific targets (although drones can--drone warfare changes things somewhat). Drones notwithstanding, there's always a strategic need for placing humans with weapons in a particular location where they're going to get shot at, and you can have your story revolve around those kinds of situations.
The first layer of the
defence onion is, "Don't be there". But more often that not, you have to be there, because if you're not there, a strategic objective fails. What happens when you're
there is what epic war stories revolve around.
