This question just recently began occupying my contemplative mind. Here's a scripture that seems to apply. Exodus 20:20 "Moses said to the people, 'Do not be afraid. God has come to test you, so that the fear of God will be with you to keep you from sinning.'"
I'm not going to try to say yes or no to whether God planned the fall but it is a new concept for me to consider that the "fall" as I have always considered to be "evil" or "bad" may have been exactly what God wanted to use to teach us to fear him - not our circumstances - from the very beginning.
I've recently began viewing everything in scripture as relationship issues rather than dos and don'ts (good/evil). It's been fascinating.
We claim that God loves us unconditionally. I have discovered that my relationship with God is greatly enhanced more by my struggles, trials/tests etc than by perfect obedience without questions. I'm not saying that disobedience is good. I'm saying God allows us to be maturing children so that we can grow into deeper relationship with him.
I've seen children who are so compliant that they don't know what to do away from "normal" situations. They don't question and attempt to reason because they fear consequences more than they fear the authority figure over them. When we have a healthy fear of the authority over us rather than merely avoiding consequences, we strive to get to know the person so that we can understand the consequences.
I also wonder if the "fall" was a test to teach us how male and female must work together. Looking at the events that took place seems to represent the same way men and women communicate today.
Is it possible that Eve failed to express all her thoughts - assuming that Adam comprehended her reasoning - while she acted more out of emotion than logic? Is it possible that Adam misunderstood Eve's intentions because he failed to enter into conversation with her - he assumed she was processing information the same way he did - without emotion - therefore he could not encourage her appropriately.
Emotion and logic are equally significant in decisions. God calls us to be full of compassion as he is and he will give us the wisdom to administer mercy, grace and encouragement. We must consider the relationship aspect of our decisions along with the logic for each circumstance.
I find the story of Job and the response of his wife to be a very similar lesson. We cannot throw out emotions. They are part of God's design for us. We are limited in our ability to reason, therefore human logic is not always accurate. The question is how do we use our God given emotions along with God given ability to reason logically to discover the wisdom he offers in each situation we face.
Just my perspective - not conclusive.