I beat the game with Mage, I used all my gear - ranged weapon, melee weapon, helmet, torso & gloves, all to boost my Abilities, didn't use them for physically attacking or for armor.  The 4th Mage ability was a instant kill on everything but the bosses.   
  
I suspect some other abilities are just as good, depends on your character build.  It doesn't have to be about who has the bigger stick