It's definitely a hard problem, but also an extremely important one as real life democracies also suffer issues like this to some extent. Obviously you'd need a bunch of rules around who could vote to prevent brigading, e.g. tenure and activity on the forum at a minimum.

But also, this could be an excellent platform to experiment and discover systems that DO work. I think it's worth trying in any case, as the status quote already "doesn't work" in an even worse way. Special interest groups grab control and there is no way at all to unseat them.