We the People have vast experience of what is needed and works. We must have input in the final decision. Participatory Democracy would give us this. We must demand it and develop the procedures to fit our government and communities. We must plan for the future and our grandkids future. Our Planet has needs we must develop and produce.
Maybe only "major" bills and are only during presidential elections when over 50% of voters turn out (2012, 2008). Barely 40% vote in off-years (2010, 2006). But seriously, the American electorate is generally too ignorant and/or apathetic to vote for president. The idea of putting hundred-page (often longer) Bills in their hands is not a serious one.