DPS with the simplest rotation would be Red mage or Dancer.

Red mage requires a bit more situational awareness for ressing people. The rotation is pretty much charge black and white mana by alternating your veraero and verfire combo with verstone and verthunder. Then use a melee combo to deal high damage.

Dancer is just proc based. A portion of your DPS is going to the party. The situational awareness for this job is to coordinate buffs with the party (but it's more like just never miss your Standard Step and Tech Step when it comes up and you'll never drift from your burst windows).