There's a lot of 20/20 hindsight in all these perspectives. The question is not whether Japan was going to surrender, the question is when was Japan going to surrender and under what terms. Japan wouldn't have gone to war in the first place if we weren't calling for their withdrawal from China. How much would Japan have given up and when? It's not what we know now, it's what we knew then and we didn't know a lot. Example: we'd been firebombing the shit out of Tokyo and they hadn't surrendered.
The targeting of civilians wasn't novel on either side. The post-war considerations were definitely important. And I am not Daniel Ellsberg. But I have a more than passing interest in this question, have held positions on both sides of the debate at one point or another, and haven't seen anything that compels me to regard it as a settled issue in 30 years of looking.
Marshall Plan terms were extended to the USSR. Stalin rejected them. Peace Love and Capitalism was open to anybody who would sign the IOU; the notion that we were destined to stare at the Soviets over gunsights is just as revisionist as framing Hiroshima and Nagasaki as a part of the Cold War instead of part of WWII.