I want to share my pure mage experience on legendary difficulty. I find it very easy as long as I have a follower tank (love you lydia). It was so easy that I had to max difficulty and playing legendary since then. My mage still dies to wolves on 1 hit but you have too many methods to evade enemy when you have apocalypse spell package. When you can get your conjuration up, it is even getting better. It is challenging some times, when I cant find a good position to hide. Mages are not meant to survive when they got hit. Trying to use all magic schools together, alteration is especially very useful with spell package. Alchemy can be very powerful when you start spamming slow time potions. You do not even need any follower/summoning help when you have a big pocket full of slow time potions.
