Mulligans
Midrange elemental mage, Open the Waygate is just an endgame burst to attack twice with minions / fireballs face.
9 fetch-a-spell effects + 2 cabalist’s tome for potential 15 spells total. That means you have to draw 10-12 cards of your deck on average to be able to finish the quest, but some spells you fetch might be unplayable (e.g. Shatter), so probably will take longer.