The role of a second parliamentary chamber is hotly debated across the West at the moment.
Countries where both houses are elected and enjoy equivalent powers (like Italy or the US) complain that this arrangement slows down lawmaking, in an age where everything else is actually speeding up.
Countries where the second chamber is not elected, like Britain, experience a certain unease: they wage war oversea "to bring democracy", and then half of their lawmaking is in the hands of a completely undemocratic body with dubious legitimacy.
Countries where the second chamber actually represents different bodies from the electorate (like Germany) seem to have found a pragmatic third way, but then this chamber ends up over-representing certain interests (in Germany, local ruling classes and their nests of semi-private special businesses), which again is not really democratic in nature.
I think we'll have to learn again why balance is required in matters of such importance, and we'll probably have to learn it the hard way. The major supporters of "streamlined" government have always been tyrants and oligarchs, after all.