Templar
Templar has single target damage close to that of a full-hp gladiator. Although it isnt the highest single target damage, they more than make up for it with their aoe damage and support capabilites
Templars are able to aoe damage close to a wizard's due to their different set effects: the 140/145 sets give damage to their physical damage aoe, and the 120/125 set gives a 50% damage boost to their magical damage aoe.
Furthermore, they are able to give massive damage buffs to their party. Their 145 helmet set effect gives 7.5% physical and magical damage, buffing every damage dealing class in the party. On top of that, they are able to use their light orb skill to increase their party's damage by an additional 30%.
Templars also have incredible sustainability support. Light mark decreases the damage that allies take by 9.5%, and they have several different shields and healing skills as well.