I've come to the conclusion that Blizzard II needs 2 things.

1) It needs to be a ranged AoE, same specs as Freeze, keep its current potency.
2) Give it a "Fire I" type of trigger, 40% chance to increase potency of the next Freeze by 30%.

This would fix Blizzard II and make it useful. As it stands, it's a worthless extra button once you unlock Freeze.