I personally side with those who think the square has been wildly successful. Even in Soho's photo, on a cold day, there are enough bodies just taking in the sun, something I've noticed frequently even in not-so-great weather. I have lots of photos of squares in European cities that are so populated, empty except for a few morning dwellers taking their coffee, but later in the day you couldn't get a seat if you wanted to. Expecting Dundas Square to be fully occupied at all times is setting the benchmark a tad high.
Besides, no matter what you did, the square is off to the side of Yonge Street. It's not a natural place to cross, and no amount of "design" would change that. I think the photos, which shows a number of people clearly off to the side of life's pageant, taking a little pause, is wonderful and perfectly appropriate for the square.