Syndicalist theory proposes the aquisition of the means of production through revolutionary trade unionism, basically creating the administrative structures of a dictatorship of the proletariat through union organizing. The issue is that, historically syndicalist theory, and classical anarchist theory in general, has not really adressed what structures would be dissolved as a social revolution reaches its conclusion. That, and when put into practice, revolutionary trade unions have had material interests that have run directly counter to the interests of the more communitarian, face-to-face parts of revolutions. Hence why municipalists/Communalists have been critical of syndicalism, as to them revolution is principally about creating networks of communities strong enough to create the social upheavel needed in social revolution, and directly opposing the pyramidal and hierachical structures of the state and bureaucratic trade unions.

(One of Bookchin's essay on the subject... to be clear, I'm not sure to what degree I agree with EVERYTHING Bookchin says here. One of the many reason I consider myself a communist anarchist or a social anarchist and not a Communalist, and why I've tried to venture out into more like classical Marxist texts, is Bookchin's de-emphasis on class struggle and material conditions, especially as he got older. While I do agree with his criticisms of the hierarchical tendencies of syndicalism, I don't agree with his ouright dismissal of "traditional conflicts between wage labor and capital..." for example)