So you're saying that a mere human, saint though he be, can change the mind of the Almighty God? Sounds absurd to me, TBH. And Abraham didn't change God's mind. God knew that Abraham would ask, and God knew the answer he would give. And also, Abraham didn't ask that the innocents be spared. He asked that the cities be spared if even ten righteous people could be found there. And since only four could be found (Lot, his wife, and his two daughters [and even then, the daughters were kinda dubious]), God destroyed the cities.
I know I sound like I'm being aggressive, rather than curious, but but so far the points you've made are unsupported by scripture, and the scripture you've used to support your arguments are misquoted/taken out of context.