Its hard to say what would have happened if he was put into power long enough to see it through. There are so many ideas, negative ones, that spawned from his school of thought. Stalinism was just one that comes to mind for me. I am glad he is not another on a long list of evil people in the world.
I think that had Vladimir Lennin's life not been cut short, he would have been just as brutal as Stalin. And considering Lennin had the power of the Russian military, one of the most commanding forces on Earth at the time, he would have been even worse than somebody like Stalin.
I believe Vladimir Lenin may have been just as brutal as Stalin, had he survived longer. The truth is, is it's difficult to guess what a person may have done given more time, so I think guessing on this topic is somewhat pointless given that history went in a different direction.
While it is true that Lenin's dictatorship from 1917-24 was indeed brutal, with millions of Russians perishing due to war, famine and political oppression, it is important to understand that this was an end towards a means for Lenin. Lenin was devoted to the creation of a better world, a communist utopia, and therefore let nothing stand in his way of trying to achieve it. And while this did of course result in a brutal regime it was perhaps considered necessary by Lenin. Stalin on the other hand was a man characterised by an acute lust for power, paranoia and greed. It is highly unlikely that the innumerable victims of his repressive, totalitarian regime were murdered in order to achieve communism. In fact, it could be debated that Stalin was never a true Marxist at all. For example, when Stalin initiated the Great Purge of 1936, which was to claim the lives of hundreds of thousands, it was done to merely remove any potential threats to his power. Therefore, while Lenin was a brutal dictator, it is highly unlikely that he would have became a Stalin.
Lenin began with a vision. His vision did not include being an oppressor. Lenin wanted to create a valid form of communism to rule over the USSR. Lenin proved to be a tough political adversary, but this was all for his people. Stalin tended to err on the side of the Soviet Republic rather than the Soviet people. This is what made him famous as a brute and a dictator. Lenin was less prone to this behavior.
No, I don't think that would have been the case. Stalin was a monster, with at least as many mental issues as contemporaries like Adolf Hitler. While Lenin was hardly what I would call a paragon of virtue, the man was more of an intellectual. I think he would have found more peaceful solutions to the USSR's problems.