I'm always a fan of tons of CC over Shields, but if you want an alternative to 2-3 Freezes, I quite like the idea of Skull Shields in this. It's not only a strong shield in its own right, but it also synergizes perfectly with the Afla ability of Greys and Dry Spell as well.
Purify is situational and I would pack more CC or quanta most of the time, but it's up to the situation.