You have to assume that everyone knows enough about everything to be able to vote meaningfully, and that everyone will be completely moral about how they vote.
I just remember a vote last year, but don't remember what it was about. It was pretty complicated, with different options about three different but connected proposals and one journo figured out that voters had 600-something different options where to say Yes/No and make their crosses on the ballot.
Needless to say, almost nobody even bothered to begin with ... the rest probably just played battleship with their ballot cards.

But on the whole, I must say it works pretty good, albeit slow. Also, I certainly wouldn't go as far as saying that a professional parliament decides on a better knowledge base than the general population. But then again, your Congress and Senate might be different from ours, although I have a hard time believing that.