If you think war was ever honourable, you must be seriously delusional. War has never been honourable, its always been just a gigantic cluster fuck with innocent people dieing left and right for some retarded asshole who calls the shots. But since you brought up Roman times, lets take a look at specifically made war in Roman times also stupid.
Champthrax said:
You were often fighting to protect your lands and families from massacre, and a single skilled warrior could make a difference even against difficult odds.
Most soldiers still think they are fighting to protect their lands and families (as to the amount that actually are, and are not fighting for the political ideals and greed of there current leader, is a matter up for debate). As for the single skilled warrior. In an all out way it didn't make much difference how skilled you were, and real life isn't a movie where one guy stands against and cuts down an army of 100.
Champthrax said:
By skill, I mean that a medieval or Roman warrior for example, could train all their lives in the art of warfare, and could become exceptional in single combat.
Some soldiers still train for years even now and will become exceptionally good at shooting or close range combat. The amount such skills influence whether you win or die in a gigantic open fight is probably minimal at best, when you're just slashing at anything that moves.
Champthrax said:
Almost everything that kills you in ancient warfare was preventable, for example, you would not have been disembowelled if you had parried, or you would not have an arrow in the knee if you had had your shield up. Modern warfare on the other hand, can get you killed in a million and one ways that you have no way of stopping or preventing. You can step on a land mine, a plane can drop a bomb, artillery can blow you to kingdom come. There are far more things that can kill you just by being in the wrong place at the wrong time, so dumb luck has a far greater effect than skill.
You seem to have a very mythic view of ancient warfare were every fight revolved around a couple heroes going at it, every other soldier was just background noise, and the outcome of that fight would be decided simply by the hero's fight. Don't get me wrong it makes for great movies and stories (which is preciously why that is a lot of what you see), but it isn't realistic to think that everyone forms a circle round the generals and watches them fight.
As for random stuff that could kill you, sure it is perhaps more limited, but off the top of my head, you could be killed:
1) An arrow fired into the fray
2) A scared horse/elephant running around after a failed charge
3) Another soldier stabbing you or cutting your knee while you weren't looking
4) Any form of other projectile weapon
Champthrax said:
It seems like individual far less relevant, since any emaciated 14 year old can pick up an ak-47, and be a threat to even a modern warrior who has trained their whole life.
You have obviously never fired a gun or you don't remember the first time you fired a gun if you think it is that easy to hold a gun on mark and accurately shoot something. He'd be as much a threat as you would be if I gave you a short short gladius and threw you in the coliseum versus a Centurion. You put the kid and the soldier both at 30m and 999 out of 1000 that soldier will win.