There is a plan for all people to live under a secular and universal religion, called Humanity One, turns out that more than one person has had very similar visions of a new religion that will transcend borders and all other religions, believing in one God and living under His true rule, The Ten Commandments.
Religion is one of the main causes of war. Wars that have been started because of religion date back thousands of years. World War II happened mainly because of religion. (I know that the Jewish people were not at fault). If anything, a world without any religions would likely be better than a world with religions.
For their acceptance of revelation from both Abrahamic as well as Eastern sources, Baha'i is probably the religion which seems to most closely fit with the proposer's "Huminity". They are viewed as apostates by Islam, and subjected to relentless persecution.
Secularly developed answers from fields like science and morality are superior to the "revealed" answers from religion. Over time, this causes an erosion of religious authority, and lessens the prospect of violence occurring for the reason of religion.
The problem is that religion is not the only, or even the primary cause of violence. Many of the most violent and devastating wars were fought for political or economic reasons, and even in "peacetime" tremendous loss of life can occur within a country for political and economic reasons. Religion historically provides a poor bulwark against this kind of violence - even within the same religion like Christianity, for example, Europe was always fighting until it became more politically integrated.
Political and economic interdependence is therefore a better means to a peaceful world than unity of religion.