PMDs are key weapons in playoffs

After watching Nicklas Lidstrom, Brian Rafalski, Sergei Gonchar, Scott Niedermayer and Chris Pronger in the NHL Stanley Cup Finals these past couple of years, we must conclude that in the new NHL, puck-moving defensemen are a key ingredient in the over-all recipe of a Stanley Cup champion. Is this true, or does it fail to stand up to objective analysis? If it does, how important is this ingredient?