Stolypin was killed in 1911, 3 years before WWI. So maybe if he wouldn't have been killed... But you know, we can go on forever with the "what and ifs".
I haven't studied Stolypin thoroughly, but I don't think that Stolypin's reforms would have worked. He was not a democrat, he wanted to strengthen the tsarist state by undermining the autocracy (shifting power from the court to the national institutions) which created enemies from above (the court). Second, he ordered lots of deportations, executions and abolishments of any critics which created enemies amongst the educated classes. Third, he was so occupied by changing the system and wanting to transform the lower classes into the new system which he had in mind, that to my opinion, if he had lived, he would have gotten the same problem as communism: forcing a system from above without talking to the people and considering what they want or need or even how they live is not gonna work. Except for one point: communism had more adherents, Stolypin was alone. When he died, all his reforms died with him.
I think he started well but after a while just got buried in his own ideas that he forgot to communicate, look for compromise. You can not force something from above without first connecting with the people you want to reform.
This way you can compare Stolypin and even communism with today's failing development aid. I'll give a short recent example from Liberia: western developmentworkers were trying to introduce a new, more resistant rice variety to better the farmer's situation. So they gathered the men together, held a long speech about why this ricevariety was better and should be planted, afterwards they send the men home. After the harvesting season was over, they came back and realized that none of the rice they introduced had been sown.
What was the problem. Well, the growing of rice is a women's business in Liberia. Men have nothing to do with it.The women can recognise 30 different kinds of rice by eye. Since the developmentworkers assumed the men were in charge, the women never heard the explanation and when the men came home with the new rice, the women cooked it.
What I'm trying to explain with this little anecdote is that if you try to force something on people (even when you have good intentions) it doesn't work unless you first connect with them (the importance of anthropology). First you have to understand, then teach and the suggest
I think that even if Stalin wouldn't' have existed, there were plenty others (Trotsky?) to take his place and act "from above", maybe not so many would have been killed, who knowes. I don't.