We need God because we are either unable or unwilling to lay aside our own wants and desires enough to solve the major problems of the world.
You do realize that we are just now entering a time where a good majority of people
don't believe in god, right? You do realize that, throughout history, nearly the entirety of mankind has had fanciful beliefs of some god character, right? Or are you saying "everyone needs MY god" because you've determined yours to be the right one and your god just happens to be the one that will "save mankind from itself"?
I am pessimistic in my expectation that humans shall ever overcome these problems on our own.
Do you have any evidence that there is a god character that will assist in this "dilemma"?
As to why we are flawed,
Funny thing about that: only you religious people seem to think humans are "flawed" and that is merely because YOU can't measure up to your imagined sky creatures. Humans are humans and we do human stuff; some bad, some good. Some bad has come from god believers and non, some good has come from god believers and non. Belief in fairy tales has done nothing for the advancement of society, but it can damn well be argued that it put the brakes on society (the middle east before islam? The dark ages?).
"Science is interesting, and if you don't agree you can fuck off." -Dawkins