So you favor a single house, all proportionally elected. I'll concede that you are consistent to that degree.
But why have a representative government? With communication as simple as it is today we could use biometric identification o allow a pretty reliable direct vote on every issue of governance -- a pure democracy is in our grasp.
The Founders were essentially Classicists. They wanted a government modelled after the best Greek Democracy and Republican Rome had to offer, tempered by the lessons from each that resulted in the rise of the Tyrant, and tempered by the lessons of English Parliamentarianism and it's eventual failure in the English Civil War, a failure that again resulted in a resurgance of the Tyrant. In all three, it was the unbridled passions of the people that they saw as the main aid to the rise of tyranny as eaither a reaction to or manipulation of democracy. Caesar did not rise to the top thu the Senate, it was his control of the Roman mobs that allowed him to maniplulate the Senate, something which they would see as now possible due to our direct election of Senators and I think it did happen in the railrioading of this country into Iraq. The lessons of the English Civil War were applied as well, although you will never get right wing "Christian Nation" religious kooks to admit, the mob was this time inflamed by religion and the Founders saw fit to deal with that as well.
The Founders essentially combined the two major features of England and Rome-Paliament and the Senate, making them co-equal in power, underpinned the Parliament with Greek universalism and the Senate and President with Roman Patricianism, and then added their own unique feature, the removal of the judiciary from subserviance to the Executive into a co-equal branch of government, a balance that Bush tried to destroy during the infamous Gonzalez episode for which he and Cheney should have been impeached. It was essentially the election of a Democratic Congress and the return of Check and Balance that defeated Bush's attempt to complete his vision of a neo-fascist presidency, where even the Law itself was a toy for the Executive.
The founders rejected direct democracy because history shows the mob eventually elects a Tyrant to correct its own excesses or in response to emotional argument, like Hitler or Bush, for example. There is more to society than the passage of laws, there is the necessity for the guaranteeal of rights. The co-equal branches of government are designed as much to that as they are to pass laws. A popular democracy would simply vote away the rights of the minorities and ham-string the courts. IMO, we should either return to the Founder's original model or simply return to the British model, which I think has in the end turned out to be the better form of government, better than the bastardized psuedo-democracy, or actually the Dictatorship of Capital, that this government has become.