Have you seen California's ballot (they have a lot of referendums)? It's like half an inch thick. Almost no one has time for direct democracy, and even if you do have time to go through the ballot carefully, you're still underinformed on basically all the issues unless you spend days researching. And this is for relatively wealthy, educated people -- imagine all the (majority of) Americans making < $50k a year, many with multiple jobs, many with children or elderly relatives, many with health issues, having to stay informed on the finer points of ethanol refining or what have you. Direct democracy is a super bad idea.