When you consider alternate past timelines, you have to choose some model: is space-time elastic so that a change will be automatically fixed gradually through

When you consider alternate past timelines, you have to choose some model: is space-time elastic so that a change will be automatically fixed gradually through time? is causation effective immediately, leading to possible paradoxes (killing your parents)? are you actually making a branch? Well, if we consider the last choice (which, I think, is the more convenient for speculating), you would still have a World War because this event was more of a pretext since there were already a lot of political tension. Moreover, the alliances which made the war global were already in place and would lead to WW1 even with another trigger. That say, you can also consider the Butterfly Effect meaning that changing the trigger could finally change a lot of things after some time. Maybe Hitler (or his substitute) would have listened to his adviser, or he would have declared war with USSR, or Manhattan Project would have failed, and so on. tl;dr: if we are to rewrite history, let us do it all the way!