I suspect that's exactly why it's not being included. Since using tadpole powers in this game is directly tied to some sort of negative outcome as the power corrupts you. They probably thought that having a class that was all that wouldn't make sense since that would mean either using any aspect of your class would advance the tadpole, or the gameplay and story would be out of sync as using your sorcerer powers arbitrarily don't trigger the tadpole.
