I've never been keen on systems which just have random "dragon" or "tiger" or "wooden chair" styles which may as well just be numbers or letters which just add a bonus or penalty here and there. And paper/scissor/stone type styles are too random (and are still just words which may as well be letters).
I don't know the solution, though. Maybe just a crapload of maneuvers you can learn, and if your opponent knows the counter, he can use it. Or something.
I always thought the 4th edition fighter stances (or maybe even the new Path of War martial maneuvers/stances) are a good point to start when trying to duel. The "bloodied" rule made it clear that anything above 1/2 HP was simply wearing off the opponent, so "to the first blood" is easily possible. It is quite mechanistic and not perfect though. You'd still need a gazillion of feats or levels to make this "maneuver & counter" stuff (i.e. "I charge with Lion's charge" vs. "I use Hold the line") work properly, at least when trying to stick to the rules.
In my opinion, you can duel quite well with martial-oriented classes like the Swashbuckler or the PoW flock and a good bit of creativity and imagination. Striking with your foot at someone's leg can be a feint that denies the opponent some action or bonus. Knowing wich maneuver to parry (& maybe riposte) is key to your survival.