God created Adam and Eve initially to have a limited knowledge. They were like children. Over time humanity would have grown and matured to a state in which they had a full revelation of God, and of truth, of goodness, and beauty. Clearly this process is God’s good plan for humanity. God did not create us to be in this final state right from the beginning. Why is the process necessary? We don’t know yet.
God probably created the angels the same way. The angels probably have their own process which God is maturing them through to a final and perfect state. We don’t know that, but it makes sense.
This process, both for man and angels, does not require evil. Any theodicy which claims that evil is necessary for God to accomplish His goals is a lie. Evil did happen, and God allowed it, but it was never a necessary component to creation.
Another parable [Jesus] put forth to them, saying: “The kingdom of heaven is like a man who sowed good seed in his field; but while men slept, his enemy came and sowed tares among the wheat and went his way. But when the grain had sprouted and produced a crop, then the tares also appeared. So the servants of the owner came and said to him, ‘Sir, did you not sow good seed in your field? How then does it have tares?’ He said to them, ‘An enemy has done this.’ The servants said to him, ‘Do you want us then to go and gather them up?’ But he said, ‘No, lest while you gather up the tares you also uproot the wheat with them. Let both grow together until the harvest, and at the time of harvest I will say to the reapers, “First gather together the tares and bind them in bundles to burn them, but gather the wheat into my barn.”‘” (Matthew 13: 24-20 NKJV)
The good seed does not require the tares. In the end, the good seed grows into what it was meant to be regardless of the tares. God is unwilling to destroy His creation even though evil has infected it. He is also unwilling to stop the maturation process for humanity because of evil. The process of growth continues despite evil, and all will be sorted out in time. Why did God allow evil in the first place? Probably because to prevent the evil in the first place would have meant aborting the process. So, while the process does not require evil, the process would have been aborted in order to prevent evil.
The goals which God had in mind for His creation at the beginning never change. If evil was not in God’s mind at the beginning, it certainly is not in His mind for the end. The perfect consummation for creation God planned for from the beginning will happen, without compromise, without loss.
Related reading: The Fallacy of Theodicy; The Alpha and the Omega and the Foundation of all Correct Theology; What God Wills and What God Permits