Let me ask you a question. What would you say was the purpose of our creation?
Why did God create? Obviously, I wasn't there, but the following is my conception. I agree with the picture that sees God's most essential attribute as being love, or the impulse to love. Stated simply, God was lonely, and created all things as a projection of his own nature, so that by being able to see and relate to all creations, he could feel joy through satisfying his desire to love.
But I don't see evil as being part of, or necessary, for the fulfillment of God's purpose. Perhaps the risk of evil was inherent in creating beings with free will, and a responsibility to take part in their own self-creation, but it wasn't inevitable. People are meant to be fully God's children, in his complete image, with the same capacity for freedom and love as God. But in that we have not been able to realize that image, God's purpose is still incomplete. And I would say that God himself is suffering and in pain, even more than we suffer, due to the violation of his purpose.