What would the world be like if there was no god?
The world simply will not exist.How do you know that for sure?
And...what would god(s) look like if there were no humans? ;-)
Anyway, I'm with what honest said above: sin is invented to control people.
It's very much the same as companies do nowadays: first make up a (imaginary) problem, then sell people the solution.
Nobody needed smartphones until companies told us we need them. Thus we give our money to smartphone sellers.
Nobody needed redemption until priests told us we're sinners. Thus we give our money, obedience and time to the priests.
Do you see a similarity there?