What are the motifs in Stone of Tears by Terry Goodkind?

Control and power are recurring ideas in the story. There is a lot of power in the book, much of it in the form of magic. Even when the power isn't wielded by a person, power seems to be controlled, such as the wizard towers in the Valley of the Lost. The towers don't have a person that controls them any longer, but the power is still there and to some extent still working.