"Why the fall?" is explained quite well in Romans 9. The reason Jesus hasn't returned yet is because God is merciful and desires to show mercy. Show true love and mercy to someone today as a testament to the truth!
Romans 9:22-23
What if God, willing to show his wrath, and to make his power known, endured with much patience vessels of wrath made for destruction, and that he might make known the riches of his glory on vessels of mercy, which he prepared beforehand for glory
That is true. We must always keep God's greater plan in mind when thinking about any judgement he makes. He is not lax concerning his promises.
What I will try to answer in the next post is the more immediate issue, which people sometimes do not fully grasp. I have seen people accuse God of juvenile actions, yet I disagree that we can judge the judgement of a Holy God. However, as with many things in the Bible, there may be a deeper story here than we realise, and I hope that the view I will present, which I only recently discovered, does shed a light on the events of the Fall.
Romans 3:3-4
For what if some were without faith? Will their lack of faith nullify the faithfulness of God? May it never be! Yes, let God be found true, but every man a liar. As it is written,
Amen!