Here is another article, also urging play over kill-and-drill for preschoolers.
http://braininsights.blogspot.com/2010/08/brain-fact-early-childhood-programs.html
I am for hands-on, but I want to be clear that play is not aimless.  I would not urge aimless, non education  during school.
“Drill and kill” may be correctly labeled. Early childhood educators should be well aware of the importance of play. However, we might make a little balance or clarity by leaving room for directed play. Huh? Okay, what I mean is like in the Montessori Method, the children choose their work, but the environment is prepared. So the children have the delight of play, while they also tend to cover the “learning objectives” that educators might want. And similarly in “emergent curricula” sometimes we have a list of learning objectives promulgated for instance by the state government. So when it is raining, and the children make damns, we might see that as an opportunity to talk about hydoelectric damns. So we are NOT talking about “dry 2D boring stuff” nor are we talking about play as in “go amuse yourself on the tarmac.” Play doesn’t have to be aimless. In good preschools, we do have directed play.
Of course, there should be time for children to really play, really manage their own time, really occassionally be not directed.  This is vital and so rare these days.