'Populism' is only dangerous when the ideas aren't yours. Populism is, ultimately, a psychological effect of democracy - it outlasts representation. Sometimes buried in the language of 'rights' and 'freedom,' it nevertheless constitutes the public face of grievance even beyond the parliamentary space designated for it. The only thing that would need to happen in order for a true populism to turn into something more would be for someone to come along who could answer their grievance in the form of a service.
This would completely undercut the function of the state and reveal its impotence in the face of twenty first century challenges. Ultimately, populism offers a model, raised to the level of popular mediocrity, as to how certain desires and projected ways of life might gain net value which extends beyond what is available merely through parliamentary and democratic processes. The disparaging way in which people often talk about populism only reveals their universalism (their willingness to use unilateral force across the whole world in order to encourage/extend certain values) and betrays the degree to which they could live the life they want with others who feel the same.
Panarchy/polyarchy seems inevitable. There still remains the question as to whether or not 'nations' as such can still exist in blocs which ensure the security of broad regions with multiple value systems operating within one culture. The challenge will be the new forms in which different populisms ally, and how to keep these alliances from drifting merely into mass monetization schemes like the EU.