If what you say is true about all trades being 1-for-1, that seems more like a bug than a feature; if an agent doesn't have any votes valuable enough to sway others, it seems like I'd want them to be able (i.e. properly incentivized) to offer more votes, so that the system overall can reflect the aggregate's values more sensitively. I don't have a formal criterion that says why this would be better, but maybe that points towards one.