All evidence indicates that human beings started out well enough. Traveling. Discovering cool things like fire, wheel, language, dance, music, art, and what not. They were open-minded, humble, inquisitive, curious, generous, and didn't worry much before sharing their knowledge. The term "Patent" wasn't coined back then. Money had no meaning what-so-ever. But somewhere down the line, we lost our way. Boundaries were marked. Money was invented. Various divisions started appearing in the society. Religion, wealth, gender, race, caste, everything started defining who we were. And soon enough, these divisions became our identity more than our original human self. Instead of curiosity, we started looking at new ideas with suspicion, and then began persecuting thinkers, inventors, discoverers, philosophers, and all those who had so far carried the civilization forward at such a breakneck speed. The change didn't stop there. Gradually we realized the monetary value of new inventions and money became the primary reason for everything. We forsook everything for money - our environment, our honesty, our humanity, and even our future generations.
But there was one thing - one power - that survived, and that till date may be the only reason why we haven't yet killed each other off and blown up the earth. It was the ability for our soul to reach out to us even when we are neck deep in stepping on each others' toes. The voice of our soul - also known as our conscience - always knows right from wrong and tries to warn us. If there was one thing I could change in this world, I would make our conscience stronger and more compelling.
I believe that everyone, even the most horrible criminals, have this little voice in the back of their heads that keeps on telling them to stop doing whatever they are doing. But our reasonable self doesn't leave any stone unturned in helping us subdue this voice with excuses. Thus we hear rapists say "It was the girl's fault. Why was she out at 9pm?", and we hear the terrorists say "We are killing these people for the greater good of humanity." And this is what enables politicians, policemen, government officials, and other people in power to continue in their regular hideous ways. The excuse they give themselves and the society is "everyone else is doing it." or "It is difficult to stay honest in this corrupt world." But somewhere deep within, they know that what they are doing or have done is wrong.
And now imagine a world where our conscience was so strong that it couldn't be overruled by our reasonable selves. Imagine if it was indeed our conscience that was the ultimate decision-maker. How difficult it would have been to harm anyone then? And even if someone did commit a crime as a knee-jerk reaction or in a fit of rage, the conscience would ensure that the criminal isn't able to sleep at night and seeks punishment or forgiveness.
And imagine this right from the time human beings started roaming the earth. World today would have been a completely different place. We wouldn't have killed off entire species of animals for sport. We wouldn't have waged wars against each other for every excuse. We wouldn't have wielded the nuclear weapon. Imagine a world full of curious, imaginative, fearless and yet compassionate people. It would probably have been a completely different place. Instead of the concrete jungles, we would have invented eco friendly housing, so as not to harm the environment much. Instead of fossil-fuel-hungry vehicles, we would have discovered green modes of transportation. Conscious of our limited resources, we wouldn't have overpopulated the earth. All our journeys would have been friendly. There wouldn't be tough restrictions on visas and no one would be left alone in sickness and old-age. It would have been a truly wonderful place.
If given a choice, from the current world I would retain the natural order, the cycles of birth, aging, and death, all animals, birds, insects, micro-organisms, living and non-living things, mountains, lakes, rivers, oceans, and volcanoes. I would have however replaced the current versions of human beings and replaced them with the versions that had a stronger conscience. I think rest would all fall in place on its own accord.