The only really questionable raids were Dresden and Hamburg I think, and that was decided at a higher level than the men who had to fly the operations. I recall seeing an interview with a German civilian who described being at a Joseph Goebbels rally in which Goebbels was extorting the crowd that they needed total war to win and getting the crowd to shout back that yes, they wanted total war. The German gentleman finished his comment by saying that Goebbels got his total war, just not like he expected it.
As to Hiroshima and Nagasaki, well, I think those saved Japanese culture and perhaps even prevented the Cuban Missile Crisis from going hot. We were expecting 1,000,000 American casualties and 10,000,000 Japanese casualties during the first part of the invasion of Japan. The Japanese knew exactly where we were going to land and had hoarded huge amounts of fuel, aircraft and other weapons for the final stand. They had tried to turn Japanese civilians into untrained, unequipped soldiers telling them to attack our men with anything they could. The Soviets would have invaded from the north as well, leaving Japan split into North Japan and South Japan as Germany was split into East Germany and West Germany. It would have been horrific.
Additionally, the full horror that nuclear weapons cause when used on people and cities instead of just unoccupied desert was made glaringly apparent to the world and, perhaps, that helped the Soviets and Americans in 1962 to find other means of resolving the crisis.
