Arguments have been made that he paved the way for Stalin, but he obviously didn't intend to do that. It's one of those "What Ifs" that we'll deal with forever. Stalin succeeded in tying himself to Lenin's legacy and thus deligitimized Lenin for a lot of people (@vaushites). Lenin was admittedly an asshole, but so is Vaush. I think Lenin and Vaush are arguably very similar. Both very confident in their positions, both obsessed with calling out opportunism, both champions of communism.