If I were you, I would focus in Magic, while making Strength and Intelligence your favorite attributes. Also, it might make more sense to use Block instead of one of your weapon skills, since you already have two skills for battle (one weapon and Destruction).
The Warrior or The Mage might be a better choice for your sign. I figure you're using The Thief because your Speed and Agility would be low, but I think one of those two other signs would be more beneficial.
Just some suggestions.
