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.