I don't understand the point of this thread, it's a very difficult question to ask and answer.
Everything that has ever happened in the universe was always going to happen, the moment the first 'thing' or 'things' occurred or became dynamic, everything was going to play out the way it did. The evidence for this statement lies in the fact that it did.
This is the theory of universal causation. Because every act has a cause, and ever act is the cause of a further act, everything that has ever happened was going to happen from the start.
And look at that, it did.
However, human minds aren't capable of comprehending infinity. Though mathematics, a product of human mind is capable of doing so quite nicely. So when we start talking about causes, we, as humans, find it very difficult to comprehend the possibility that there might not have been a first cause.
It seems unlikely, but that's exactly the point. Just because you don't understand it doesn't mean it isn't possible.. Obviously.
So we could live in a universe of infinite temporal and spacial quantity. The thing is, this is infinitely more likely than a theory based on some sort of First Cause.
(Please note, nobody would think the Big Bang is the FIRST cause, only someone arguing from ignorance would take that view)
So to ask us, ie Atheists, what we'd have done differently to God had we made the world is a strange one. Since 1) it's infinitely more likely that God 'planted the seed but didn't fashion the leaf' (sort of thing) as opposed to many Christians personal God, and 2) If we want to be sensible about it, God is an ancient fabrication first as a result of a hypersensitive instinct to 'see faces where there aren't faces', which happens to us all the time (just look at a colon next to a close-bracket) or a cat chasing around the light of a laser pen, secondly used to explain things we couldn't explain, thirdly to benefit a ruling class, 'when the first con artist met the first fool', and four because we are comfortable with answers that have satisfied us in the past and are reluctant to put ourselves in to positions of compromise (it's an evolutionary advantageous quality to have to not want to endanger what already survives).