Even if Hitler had remained one of the unknown millions of disaffected soldiers post WWI and had nothing to do with the Nazi party, or was deported after the Beer Hall Putsch, I think the course of history would still have followed roughly the same pattern. The Nazis were only one of numerous small parties of disaffected nationalists in the 1920s, the social and economic conditions that led to their rise would still be the same without Hitler, and it is entirely possible some other leader would arise and come to power in a similar way.
Well maybe a Nazi party more along the lines of the Strasser model, more left leaning, saner, less genocidal and more pragmatic regime. I am of the opinion that no one else could have taken Germany and the Nazis on the same destructive path that Hitler did. His was a cult of personality that no one else could have filled.