@lordofallhumans: Rowena is very much amped by the book of the dead and codex
That's not proven. The book has powerful spells and she can translate them, but the spell she used on Castiel was of her own creation. She was introduced as a powerful witch simply because she could kill demons which was unheard of until the colt and the very few things capable. Magically as in using magic and not acts of will she is more powerful, and Regina has better feats than Rowena and the ability to cast magic through an act of will.