That's not "a simple question" as the original post tittle suggests
For warriors, the age-old question is the extra damage of a 2-H weapon, or the better defense with using a 1-H weapon with a shield. Neither is a clear winner, which is part of the game being balanced.
It really comes down to player preference, and which Skills you want for your character.
2-H weapons (swords, axes, mauls etc) offer a higher Damage Per Hit and often (but not always) a higher Damage Per Second. There are warrior skills that are better suited for the use of 2-H weapons and there skills that are better suited, or require, 1-H weapon (and shield).
Keep in mind that since 2-H weapons only get damage from STR, a 2-H build is likely going to be very high in the STR trait. In comparison, since 1-H weapons get a damage boost from both STR and AGL, a 1-H weapon build is likely to have a decent investment in AGL (esp if going for Flurry),
By way of further comment, both 2-H and 1-H Warrior sword builds have beaten every aspect of the game on every difficulty level. For casual and normal, there seems to be a slightly easier time of the game for Warriors to go 2-H with near exclusive investment in STR and END. You'll miss out on a lot of quest options (still get the quest, just not the trait checks). At Ironman and Hard, there seems to be a -slight- preference for players to choose 1-H weapons for warriors to take advantage of Infantry Training and Flurry. At higher difficulty levels, the extra defense makes a difference.
Also, remember a shield isn't just for physical defense as shields are one more potential source of elemental protection.
But, it comes down to player choice more than anything.
Yes, it's a well known historical fact that platemail could stop most blows from most melee and range weapons. It's why nobles wore it. On that same note, fire arrows really weren't used that often in real life, and when they were used, really weren't that effective.
BUT, in game physics, the trope is arrows cause piercing damage.