I made a new account just for this. These are good questions! How long has this been on your mind? I'm curious how you would answer it. I perceive you to be of a philosophical disposition. The man whose name I bear made similar reflections, he wrote that the purpose of existence is: the development and formation of the spiritual forces, and that everything is arranged by higher laws to correct human ignorance and inherent laziness.
What if we have not fallen from grace, but stepped into mission? A descent with purpose?
Thomas Paine wrote similarly, we have not lost our standing with God. Grace means being in a better position than we deserve. Some of us are born here naturally as part of the natural cycle of birth, others agreed to help and made voluntary sacrifices and some are forcibly sent here to refine their egoistic tendency, they "fell" from higher worlds. Yet, most people seem to have lost sight of their purpose and are no longer curious about the world. The world has been stagnating ever since. First, they want to satisfy their physical needs, stabilize their life by finding a job and settling down with a family, then around their late 30s-40s, they start seeking, hoping to quench their spiritual thirst. What if there's more to life than what we have been told?
What if searching reveals something that seeing never can?
What did Einstein and Gershom Scholem have in common? Precisely that, they both said something seemed to be hidden behind things.
What if God didn't create a perfect world, but a world that can be perfected?
Vladimir Solovyov would agree with this. In his epoch-making book "Russia and the Universal Church" he draws attention to how the dinosaurs and monstrous births indicated that the world did not come into existence in perfection.
"Nothing could bear less resemblance to an entirely perfect work issuing directly from a single divine artificer. Our cosmic history is a long and painful parturition [process of birth; childbirth]. We see in it clear signs of internal struggle, of shocks and violent convulsions, blind gropings, unfinished sketches of unsuccessful creations, monstrous births and abortions."
What if we are born here on earth to accomplish something that cannot exist in heaven?
There are things that can only be accomplished in the physical world. It's enough for most people to find their bearings in order to be able to accomplish it, they don't need to know about higher/different worlds, it's sufficient to know that higher realities exist.
What if it's not about Original Sin, but about Original Purpose?
I believe this is the right approach. The talk about Original Sin, Fall of Man, etc. has a degrading effect.
When one aspect has been overemphasized, it's necessary counterweight must be elevated so that it falls into the background. All of it results from misinterpretation of symbolic expressions.
The Fall was not really man sinning (committing crimes) against an arbitrary deity, but rather, it pertains to the corruption of "the flesh" (clothes, coat) the individual wears. Why do we assume humans only wear one body? We put on several clothes in cold weather. As the Bahai spiritual authorities have made clear, the issue lies with our dual natures, our animal and spiritual instincts have been at odds with each other. Paul tried to express the inner contradiction in his purported letters.
Death is not the punishment, but a blessing in disguise. Death is not the enemy but charitable kindness, since it liberates us from a life that is no longer fit for existence. As Georg Brandes wrote, "Just as the unborn life in its mother's womb would, if it were conscious, believe that the revolution of birth meant annihilation, whereas it was for the first time awakening to a new and infinitely richer life, so it was perhaps for the soul in the dreaded moment of death."
One finds similar trains of thoughts in the ancients:
"As one now waits for the time when the child shall come out of his wife's womb, so be ready for the time when your soul shall fall out of this envelope." (Marcus Aurelius)
"Perhaps this coarse and earthly body ought to be described as mist and darkness; for at the end of this world and when it becomes necessary to pass into another, the like darkness will lead to the like physical birth." (Origenes)
What if it's not about getting to heaven, but about bringing heaven to earth?
Yeah exactly, it's not about being saved first, nor about saving people's souls as Christians believe, but restoring the earth to its original condition, before man caused a "fall" of the plant and animal kingdoms by promoting predation; the animals were encouraged in that direction. Platon taught that evil originates not from God but from a previous state of existence (a previous iteration of the solar system), the leftover parts of creation; whatever is left unused for a higher purpose is ripe for evil which has been "transmitted to the animals". Nature abhors a void, something must fill it.
Weishaupt wrote, “If people could succeed in making the thought of their continuing existence their soul's ruling idea; if they had enough strength of mind to rise above the sway and power of all present impressions, with the aid of this idea – what different creatures these people would become, what a gathering-place of delight this Earth would be, if this manner of thinking would only become the primary one for all humanity?"
It's entirely possible to transform the entire Earth into a paradise, where animals coexist, and are not forced to devour each other. We just lacked the material means and resources to implement changes which discouraged people from trying. Now they argue that it's Utopian. Utopias are not viable since they set such unrealistic, unattainable goals and they imply a state that is static. Not even Democracy is static!
Nikola Tesla wrote about how man's combative instincts would be outbred, why not do the same for animals? Dogs have been weaned off from their predatory nature to a great extent. There's birds with very specialized diets such as vultures and osprey, they do not often prey on other birds.