Well, Sam's proposal was ridiculous and moronic.
Liberal Democracies with universal suffrage finally developed only in 20th century !
Not to mention, that Westeros doesn't even have any legislature assembly. English Parliament was required to approve taxation or legislation.
In England various constitutional reforms and rise of Bourgeois elements happened throughout the centuries. English had Magna Carta in 1215, first Parliament in 1265, Statute of Marlborough in 1267, Model Parliament in 1295, House of Commons in 1341, Petition of Rights in 1628, Habeas Corpus Act in 1679 and Bill of Rights in 1689.
One of the biggest problems in France was that Bourgeoisie had no effective and consistent way of affecting King's policy, like in England.
Estates General were never summoned in 1484 - 1560 and 1614 - 1789, for example. Not once were Estates General summoned during those very long periods.
Bourgeoisie were able to finally attain political power and defend their interests only with Revolution.
What's the point of whole population participating in the vote, if they don't have any rights and can't represent or protect their interests ? Even Bourgeoisie class ( if I even exists ) has no effective way of affecting Crown's policy.