How about this. Instead of a random shmo like Joe Chill, the Waynes are cold-bloodily murdered by someone they trust in front of Bruce's eyes, and Bruce is separated from his little sister who doesn't even remember him when they meet later. His guardian throws him out into the street and takes his inheritance and he has to sell newspapers in the corner for a living and sleep in alleys. Does he still come out the sociopathic Bat-God or does he come out sunny and optimistic - like say Billy Batson who had all those things happen to him.
This is one reason I could never identify with the recent (well since Frank Miller) Bat-dick who uses his pain to be an a-hole to everyone. He's not the only one whose gone through so much trauma, but he is the only one with an unlimited amount of money and time so he can make a dozen bat-caves, buy bat-toys and be a jerk to everyone who dares care for him.