Actually it probably be better to kill Nikolai II before his son Alexei was born, or even conceived, the throne then passes to his brother Mikhail II
WWI can still happen, but Russia has to do better, and it very well could do better with different leadership. Even if it fares about the same there is no guarantee the Romanov dynasty will fall, say Lenin is greeted by the Royal Guard as he pulls into Finland Station, the Reds are going to be in trouble, and as I said in another thread, just as prone to fight themselves as the Whites, and if the Whites were better organized, they could very well win the Civil War.
