With the absence of Hitler, would the party have been as big an impact on German politics as it did?
Probably not. Hitler's speaking skills were what drew many people (including Goering, Goebbels, and Hess) to the party and his leadership was what allowed the party to survive the various setbacks of the 1920s. Take away Hitler and the Nazis (or DAP, which stands for German Worker's Party, since that was their name at the time) stays a tiny movement of angry men meeting in beer halls.
It's simple: without Hitler no NSDAP, no Nazi
He was Führer, who lead and control a bunch of people, who hate deeply each other.
See the way Heydrich and Himmler deal with Ernst Röhm and "communist movement" of NSDAP, they shoot them...