I like the concept, and I think it would fit the definition of democracy since it reflects the will of the people. The main issue I see is that it still remains stable if a majority superclass oppresses a minority underclass. Tyranny of the Masses is a problem with most forms of democracy, not just yours.

One tactic to mitigate it is by only doing a random sample each time instead of a full sample. So randomly select 20% of the population, require them to vote, and if 50% of them vote in favor then there’s no election. That only works if the mechanism to randomly select people can’t be tampered with, though.