...the Lamb slain from the foundation of the world. Revelation 13:8
There are some things God cannot do. One of which is to make a duplicate of himself. To do so would not only violate his oneness, but it would make him a creature. How would the original and the duplicate be told apart? Therefore, even if God desired to make a creature with personal and relatable qualities commensurate with himself, that creature would not be him, could not be as his is, or do as he would do.
The repercussion, it seems to me, in making another being with God-like capacities of will, is that it would be inevitable, at some point, that the creature would chose a course of action not only independent of God, but also at cross purposes. In other words, the creation of the image of God necessitated the failure of the image according to the standard that is God himself. This failure, being one of inevitability, would not require a specific decree in order for it to occur. It would have been a foregone conclusion given the decision to create.
I find it interesting, perhaps telling, that the first test of conscience adherence to the standard was sufficient to prove the point. I have to wonder if God would not have foreseen the dilemma (he would have undoubtedly), and allowed the efforts of Satan in the Garden to expedite things. I do not think there is any necessity for an omniscient, omnipotent being to wait around for an inevitable occurrence. Certainly, no aspect of the Fall would have caught God by surprise!
If that failure had been made open-eyed, rapprochement would be impossible because there was no possibility to learn from error. What would fuel the reconciliation? If seeing God for who he actually is did not arrest the will to "do" other than God, what could stop a recurrence? At best, a reconciliation could only last until the next time wills diverged. This is similar to the situation with angels and it is unsustainable if God is to be God.
If that failure is made in ignorance, rapprochement would be possible because one could realize his error and agree that God's way is the only way. This is the situation with man. Mankind is redeemable because it is possible for him to awaken from his ignorance (with gracious assistance of course) and realize that harmony with God is the greatest and only good.