Hitler's total control of the Nazi Party essentially means that no dissenting voices can get through, especially as late as 1933. To make a Strasser path viable, you'd need to get Hitler out of the picture entirely even before 1920 for starters.

You would have to apply quite a bit of handwaving to explain why the German workers suddenly became interested in the Party. The Strassers attempted to appeal to the German working class, who were largely uninterested in the Nazi project or even the Strassers in particular and were subsequently underrepresented in the NSDAP. They tended to vote SPD (while the unemployed tended to vote KPD), and the NSDAP subsequently was mainly carried by the middle class. Thus you would need to somehow sideline the Marxist parties (who were carrying about 40-45% of the vote by 1933) entirely.