No they are not.....................Playign a pure mage is utterly broken right now. Damage is not enough, mana goes to fast and doesnt regen fast enough, not rocket science.
I've seen pure mages playing in their 40's and it's utterly fine. With enchanting you can make schools of magic free to cast and with destruction spells you can stun-lock Ancient Dragons to death. A pure mage also has access to powerful summons, tons of self-healing and defense spells and can make enemies fight each other. Mages are incredibly strong in this game.
They only look weak when compared to broken crafting mechanics on level 60 characters.