Energy shield just sux hard.
My sorc has over 1000 mana and lvl 1 energy shield, and even with that much mana it S-U-C-K-S

Get more vitality, dont waste your points at energy shield and the pre's
Make sure you put at least 1 in frozen armor, its a godly 1 point - miracle (when i have all my synergies maxed, i spend all my skills on frozen armor)