A variation does not depend on the existence of evil. A truly omnipotent God could create all possible worlds. A "good" God can create only "good" worlds. A God that created all possible worlds would have no moral qualities whatsoever, and could be replaced by a random generator. The standard response is to argue a distinction between "could create" and "would create." In other words, God "could" create all possible worlds but that is simply not in God's nature. This has been argued by theologians for centuries. However, the result is that a "good" God is incompatible with some possible worlds, thus incapable of creating them without losing the property of being a totally different God.