I think his primary role is that of a propagandist, and I mean that in a good way, of course. His job is to highlight the hypocrisy and inherent unfairness of the system to ordinary people, and he's been relatively successful at that. I don't disagree that he's genuinely democratic socialist, but if his message did suddenly become more radical and "outside the mainstream", would he be able to reach as many people as he has been able to reach so far?