In the historical context I would see "Vox Populi, Vox Dei" as intentionally juxtaposed against the "Divine Right of Kings" (the leading political philosophy in Europe for the last few thousand years).

I think there is a TON of interesting discussion to be had on the best ways to _implement_ democracy, but locating the source of political power directly in the people who are governed seems like a pretty solid idea to me... I have not been able to come up with anything better.