Pure ownage.
Frostbolt, icelance, CoC... all will have 60% (70% CoC!), 15% chance to freeze target in place, 10% chance to treat target as frozen for next spell, 10% chance to stun target.
And all this is just for casting regular damage spells. Add on quick frost novas, ranged frost novas, frost novas when ice barrier breaks, and a 5 second stun for more CC... buffed ice barrier plus icy veins for casting even on melees/hunters... some protection against excessive interrupts/silences...
Wow.