While our government is based on popular will, it was thought proper to limit direct democracy to one House. I think our history since the 17th demonstrates the Framers got it right. While no system is perfect, I would rather risk back room deals in Senatorial selection than live through what the likes of Teddy Kennedy, Chuckie Schumer, Carol Mosley Braun, Boxer . . . etc. have brought us.
Using the premise that any event is responsible for all the events that follow - then giving women the vote was a big mistake - along with emancipation of slaves - eliminating the draft - etc, etc.
The expansion of power of the Federal government would not have been properly held in check by appointment of Senators rather than their direct election.
And you don’t think a Kennedy (rather than a Scott Brown) would be filling the seat in Mass right now if they were appointed rather than elected?