Why would Phaneuf be better long term? Meszaros might be a bit worse now, but there is no real reason to say that one will be better in the future. Of the current crop, guys like Redden and Lidstrom may lack the physical qualities of the Rob Blakes and Chris Prongers but are better defencemen. The ability to make a great exit pass and defensive awareness are perhaps the two most important skills for elite defencemen. Being able to skate the puck up the ice, shoot the big slap shot, or give out big hits are just gravy. And at this point both Meszaros and Phaneuf have shown the ability to the gravy, but what will differentiate them is their ability in the two key areas. I don't think that J. Johnson will be as good as Meszaros based on his World Junior play. At this point I would say that Meszaros is on the bubble with a few others in terms of who will be top 5 Dmen, but he is in the best position to learn how to be a great Dmen... with all-stars as mentors and in a system that forces the Dmen to be skilled.
