I have to admit, when the three 51-point Mage talents were revealed, Deep Freeze was the one I was least excited about. In its initial form, the spell was 1.5 second cast, 5 second duration stun that only worked on frozen targets. Ok.../golfclap. I shelved the spell in the dark recesses of my brain and devoted most of my time to pleasant fantasies involving Arcane Barrage, Living Bomb, and a lot of Gnomes.
Then a funny thing happened. Over several new beta builds, the spell actually became good. When I finally got into the beta and was able to take the spell for a test-drive, I discovered it was very good. Not perfect, mind you, but highly effective.
Damage was added to the spell. High damage. Then the cast time was removed, making it instant. The spellpower coefficient remained what it had been when it had a 1.5 second cast. All of a sudden, Deep Freeze was an instant-cast nuke with a reasonable cooldown that also delivered a stun mechanic. Suddenly, the spell had become...well, pretty awesome, actually.
So how does it work in practice?