Certainly, there is analytical validity int his approach. However, I am not sure if that is not puting the cart before the horse. Mass mobilization did not occur until Hitler was appointed Chancellor, the Nazis initially got less than 10% of the popular votes, considerable under the proportional representation, but not exactly mass mobilisation. Only when Hitler firmly controlled the state apparatus, he could procure, by hook, crook, and coercion, the mass mobilisation you are talking about. So I would not discount the overt role of the state in defining fascism.
That is, however, a minor quibble. Your point of including the class struggle dynamics in a particular historical context in the definition of fascism is well taken.
Regards,
Wojtek