It's very possible that there would have been some kind of authoritarian government in Germany, had Hitler not survived. There had already been one, during the war, and the Weimar Constitution had the glaring flaw of Article 48, allowing the Reichspraesident to rule by decree in emergency. That article was invoked something like 120 times in the 16 years of the Republic, which was far more often than its framers expected. And there may very well have been a racist and statis movement, especially given the threat from the Communists. But it probably wouldn't have had the same character as the Nazi party eventually had, because a driving force in that development was Hitler's personality. There were other strong personalities, in the early days and immediately after the Machtergeifung, the Strasser brothers, for example, who were every bit as dynamic and had the same or better organizational and motivational skills as Hitler. They weren't as ruthless as he, and were outmanuvered, along with Roehm. Assuming Hitler died in WWI, and they all survived, it's a good bet that they would have created the mass movement as they wanted it to be, but it's also a likelihood that they would have wound up remaining a phenomenon within Germany and not engaging in foreign adventures, at least not in Europe. I think they would have ended up like the other authoritarian and totalitarian governments in Europe at the time; that was the most common political trend (viz Franco's Spain, Italy, Poland, Hungary, Rumania, Greece, Austria).
Prost!
Brad