Yes Ben is gone. I know this, a great interior defender makes a big difference on the perimeter. His intensity and weak side shot blocking will be missed.
Do you also know that Sheed is a good shot blocker and prolly the best low post defender in the NBA?
Do you know Nazr and Dyess are also very good low post defenders? Not to mention DD who is a solid defender, or at least he was last time he came out of hibernation.
Do you realize Ben has been in rapid decline? Did you catch the 2005 or 2006 playoffs?
Did you by chance see how many championships we've won the past 2 years?
Additionally, I wouldn't totally discredit Chauncey, Sheed, Tay, Dyess, and Hunter's defensive skills with the loss of Ben.