I don’t think anybody has summed this up more intelligently, accurately or eloquently that Christopher Hitchens. Please treat yourself and check out God is not great.
In my personal view, I think it depends on where your question is coming from. Are you assuming that the existence of God has been utterly refuted beyond all reason, or are you agnostic and asuming that we have all chosen not to believe in God?
If it is the former then I think we are much better off in many ways. The whole planet will breathe a collective sigh of relief when the last vestige of this ancient load of bollocks is cast aside. No longer will anybody have to feel guilty about being gay, bi or . No longer will there be any excuse for the appalling treatment of women and girls anywhere in the world. In India there will no longer be any excuse for the oppressive caste system. Oh and as soon as anybody starts raving on about visions that compel them to butcher the people in the rival village they simply won’t be believed and the slaughter will not happen. Shall I go on?
The standard of civilized behavior in the world will raise dramatically. Why would this be? You only have to look at the difference between the most religious societies and the least religious along with the general affect of secularism and the enlightenment. secular societies positively invite and encourage curiosity, debate and rational discourse. Everything is up for examination and challenge. Along with the technical advances (Generally absent from many religious societies, or at least restricted) this has brought greater freedom for all - especially those who were at the bottom of society to start with! As it has been said before by people far smarter than me: Civilization of religion has come from without not from within. There is a reason that you are not compelled to be bellowed at by fire and brimstone preachers from the pulpit every Sunday. It’s because they know they can’t get away with it any more. People (In Britain at least) can simply say “No thanks. Not for me”. No need for revolt or riots, just a simple changing of the mind.
To return to your original point I refer to the second part of my original statement: That e are all agnostic on the actual existence of God, but have chosen not to believe. How refreshing this would be for the world. Why? Because it would mean that reason had prevailed. we could grow in confidence as a species as we used that rationality to address the greatest challenges facing the world and everyone in it. Divisions would fall between people, resources could be pooled, communities could drop pointless and violent divisions. Nobody would have any worries about endless torment after they die. How liberating would that be?
Would there be a down side? well there would be if you were a Priest, Rabbi or Mulla. No more sheep for them. People would have to accept that their relatives are not waiting for them in Heaven (Or Hell) and that would probably hurt a lot of people. How could the rest of us feel anything other than compassion for these people.How we could do more to reach out to them and show them that their loved ones live on as long as we treasure their memories and their wisdom that they passed to us. we would really be able to prove that just because we favor rationality it does not mean we are simply cold robots! We can be good, kind, happy, healthy and fully alive in every way just fine without a vicious and judgmental invisible sky-father.
I think that will do.