Killing him would only delay or change world War 2, the reason Hitler became who he the Hitler we all know was because the German people were starving due to the occupation of post war Germany. Even if you killed him, another one would take his place and possibly be even more ruthless resulting in even more death. Many people think killing Hitler wil prevent WW2 but it will just cause another person to become the next dictator that offers the people a better future. Anyone who thinks that Hitler was the only "bad guy" Is a fool and should review their history lessons. Post war Germany was full of people who wanted change and wanted to improve the life of their people wich doesn't sound unreasonable of you are starving in your own house. In conclusion, even if you killed Hitler, another one would take his place.