Tera's combat works this way for ranged classes, the closer you stay to the enemy the more dmg your ranged skills/abilities do, oh and pure dps classes do shittons of dmg compared to tanks and healers, that makes it worth to roll a dps over a hybrid
P.s. The overall quality of the game is debatable but his full action combat system and sharp distinction between class roles makes wow combat look like a card game, youf roll a priest in Tera you can't expect to be a dps in dungeon/raid enviroments coz slayer's dps is double of yours...