Class mechanics pre-Warlords: Hardest caster being Shadow Priest in DPS, and hardest melee being Rogue. Skill cap and difficulty are different, however, but not very much. One important question to ask is how much utility a class/role can provide, and how necessary it is. Shadow has almost always had a vast amount of them, ranging from various forms of dispels, heals, damage types, and more. The damage part is not harder or easier than for other casters; it is everything else combined that makes the class/role difficult and with high skill cap.