I've recently been spending time trying to play a "real Mage" (No Martial Talents, Pure Spellcasting, Enchanted robes and Alchemy) and, well, I have some beef with the Destruction and Alteration branches (or rather, the amount of headgear tailored to Mages that ruin the Mage Armor perk ex: Miraak's headpiece). The Destruction spells are way too weak to match enemy leveling (And don't get me started on dual casting), I am a level 25 Mage and I'm really having a hard time enjoying the game when I can only cast 3 adept spells (even with Destruction-based gear) and the enemy's health decreases by virtually the same amount as if I had attacked them with a dagger. I feel that the cost for destruction spells is far too high for the damage output they have. But when you are attacked by an A.I. Mage, they just spam magic like there's no tomorrow and you actually notice the damage they're doing.
My other problem is how Alteration, for the amount of Magicka it consumes, heavy armor is still better. And while I can understand this, another nagging question is why the is the magic headgear all armor? This renders the Mage armor perk useless!
Has anyone actually beaten this game as a "True Mage"? I play on Adept difficulty and I think I might just stick with Warrior since blades seem to be stronger than magic (not to mention I can attack without reducing my stamina).