I suppose you're right. We could have just sat by while the Soviets took over Japan. If the concept of a draft seems to frighten you so, or at least strike you as almost unforgivably unjust, you probably ought to emigrate to Scandanavia or Switzerland.
C'mon, seriously, all your telling us is that you don't like the draft and that somehow people should've been magically spared at war's end. You still don't say how the Japanese would've surrendered and even stated that we could have embargoed Japan in 1945, but allowed them food and medicines. How would that have induced them to surrender? How would we have prevented them from trying to regroup and launch a slew of suicide weapons vs the fleet that would've had to enforce AND carry out the terms of said embargo? Also, considereing the strain placed on the USSR at the beginning of the war, perhaps you can explain how they kept on till the end even in the face of 25 million casualties. Japan might have eventually collapsed under it's own weight, but not before the Soviets would have invaded it. How many Japanese sholud've died to satisfy one's sense of moral superiority about not using an atomic weapon? Sadly, it took the prospect of almost complete annihilation to bring the Japanese around.
Unfortunately, you're quite wrong there. Slaughtering innocents, as you put it, is one of the ugly aspects of war that is almost always unavoidable. It also tends to serve as one of the reasons people try to use every diplomatic trick in the book before they go to war to get what they want. Hitler would have been quite happy to take Europe by diplomacy if he could have pulled that off. But staggering human loss is also the main reason WW3 never happened. If not for nukes, there would have been almost nothing to stop the USSR from overrunning Europe within a decade of the war's end.