Back in my strategy concentration in Paris, we were taught that the role massive city bombing played in World War II was an emotive one, to a point. The Luftwaffe were doing too good a job knocking out British airfields in the first part of the war, so the RAF broke with accepted practice and started the massive bombing of German cities, beginning with Berlin. This produced the desired effect of nudging the Luftwaffe into retaliating with British city bombing, drawing their limited resources away from strategic bombing - sacrificing British
But did it hasten the end of the war? I don't think so. It's a sort of Law of Nature that gets drilled into you in strategy studies - Air Power Doesn't Win Wars. Maybe mutable or not, but one thing is sure in this case: Germany didn't surrender because German civilians were tired of getting bombed by the RAF, it surrendered because the Russians had arrived. And while the argument that Germany was easier to overrun because of all the important things that had been bombed is a persuasive one, I find it less persuasive than the argument that the German army and population went on fighting as long as they did because of their fury over how their cities had all been burnt down, or because of fear of what enemies who had shown so little mercy to civilians would do to them if they put down arms.
I honestly believe the Germans could have allowed fifty genocidal tyrants to come to power, and the English could have allowed their governors to go on murdering and enslaving darkies in the colonies for another 50 years, and neither group would have morally deserved to have their lives, happiness, and sanity abused by their leaders in such a disgusting and futile way. But who deserves anything anways.