I don't like Leibniz's solution, mainly because of his methodology in reaching it, but I agree with the basic premise you suggest that evil does not exist. I clarify that I say that evil does not exist in and of itself. As in, there is not a devil or comic force of evil as so many cultures have believed. There is evil in context. As in, there are actions that can justifiably be considered as evil because the actions cause unnecessary violations and suffering of others. A number of philosophers East and West have separated acts of nature from acts of humans. If a tree falls in a storm and breaks a window, the tree is not condemned as unethical. But if a human willfully breaks a window, that human is justifiably condemned as guilty of an unethical act. The distinction is consciously choosing acts that violate another and cause unnecessary suffering. There is no cosmic evil, but humans can and do create it.