I recently made a new mage character and got to 100 speech, 100 smith, 100 enchanting, 100 alteration, and 100 illusion before doing any quests at all other than Unbound. I ended up at around level 40ish. I made a full set of Daedric armor and made it legendary using a smithing set (I used enchanting potions to make a +112% smithing set and used smithing potions when it came time to actually make them legendary. I think I got my top to around 112 defence with only 15 Heavy Armor). The enchantments I have on them are -100% Destruction and Conjuration so i can spam destruction spells and summon new thralls as they die off. I also have an equivalent set that has alteration and illusion bonuses. I can use heavy armor as a mage effectively because I use the Steed Stone which makes armor weigh nothing like the perk does.
Basically I play defensively while letting my thralls or dremora do most of the damage with the option of being able to play offensively if I have no problem tanking the enemies.
