While alternative institutions are great and all, a really big weakness in dual power strategy and prefiguration is the peripherality/centrality problem, something I'm actively theorizing on. Namely, guerrillas in boondocks and dual power in cities, leftist organizations, etc. all exist as peripheral projects while the centrality of society is taken by state, capital, patriarchy, etc.
The transition between a condition of peripherality to centrality is, I think, the core of the revolutionary project. The solution by which can only be solved by means of insurrection and communization. By whom? The party of anarchy. The party of anarchy unites all peripheralities in the seizure and overthrow of the centrality.