-Vulnerabilities (many targets have vulnerabilities (undead, vampires atronachs any type of elemental mob)
-ignore armor (not that mobs have that big amounts of armor, but those less comon mobs going around in heavy armor, it matters, those special mobs going around in heavy armor/shields it matters alot)
-aoe (what does more dmg a 100 damage arrow to a target or a 80 damage spell that hits two or more?
-drain stamina (frost spells drain targets of their stamina preventing power attack and potentially fatal attacks at best, high damage taken at worst)
-drain mana (thunder spells drain mana of targets, making casters forced into meleeing you with their daggers rather than zap you to death)
-damage debuff (fire puts a debuff on targets that increases the damage they take, this is particulary awesome if you STOP thinking about using only a one hit nuke, and LEARN that you have to chain spells)
-ranged (a melee attacker does no damage to you if he cant reach you, and you cant do any damage to a ranged attacker if you cant reach him)
-stagger (I mention this perk knowing that melee has this too, but melee cant range aoe stagger being awesome to kite/train mobs into your aoe chains)
-Vulnerabilities: You need to spend 9 perk points to get full effectiveness for every element. It's not as much vulnerabilities as it is INvulnerability to the other elements.
-Ignore Armor: It's vital to ignore armor if the best spell you will ever cast does 225 damage.
-AoE: Will only kill your summon/companion and again, 225 damage is the most you'll ever do, I've seen every other "class" doing thousands of points of damage with a single hit lategame.
-drain effects: Draining stamina does nothing, most things already kill you in one or two hits without power attacks, drain mana does nothing, high level mages have basically infinite mana, NPC and player, that is.
-damage debuff: Is completely useless, the debuff doesn't stack, and is barely noticeable once you get around level 40
-ranged: So we're supposed to abuse the AI to be able to win now? Most humoids carry bows or use spells when they're out of range, and most creatures are faster than you.
-stagger: This is the only way to kill anything with thousands of points of HP, because again, your best spell does 225 with all the perks.