Everything I read about WW2 makes the outcome seem more or less inevitable, especially concerning the Easter European front. Was the outcome of WW1 less certain? If so, how?
Germany's chance of winning the First World War was slim largely because they had to fight against three super powers on two fronts with very weak allies. Germany also was very restricted resourse wise because of the British blockcade. This meant that Germany could only win if they knocked out France in the very begining of the war, but due to Belgian resistance and the unexpected rally of the French and British troops at the river Marne this notion ended pretty quickly
It is possible that a better government could have tried to negotiate peace there but that is left up to the "What If" scenarios.