What could have been the future of humanity if laws were no there? Could the society have been a little bit different from what it is today?
There would have been no future to hope towards for if there was no laws guiding people's actions. The laws are not the problem of this world, it is humans that have refused to generally live by the agreed laws of man and nature.
You are right, if only human can abide by the laws that they have made for themselves, everything will be OK in this world. The only reason we are having problems upon problems is because humans have decided not to obey the laws that they made for themselves.
We have the law of nature, humans have also refused to obey the law of nature, this shows that the only problem we are having in this world is the inability of humans to obey laws.
It is wrong and against the law of nature and the law of man to kill someone, but humans are doing it, so it is not the law that is the problem it is human.