I play my Mage save on master and i find it realy balance.
I recommend you when you out of Magicka to use staff, the more hi is your skill the more times you can use it (for exmple destruction).
its also realy fun, on a bit hi level stuff they also use impact even if you did not pick this perk

you shold have alot of soul gems to refill the stuff, so dont worry about magicka. ( i normaly put my fev staff on 8 and just use it when im out of magicka)
if you simple hate staff, i recommend the conjuration weapon, cast when you 10% of magicka left, they normaly very very strong and they can cast soultrap auto.
i think there is 2 ways to play pure mage and ensure you dont die so easy, i think conjuration works very well with destruction scholl, and illusion with resto.
you can chose if to fight as many mobs the game send on you or just use fear and mind tricks to deal with your mobs more slowly.