Yes, definitely need quicker central defenders. Our present pairing is adequate at marking but far too slow to act and intercept potential threats, especially at set pieces hence the big problem at set peices with zonal marking.
Hyppia is a good stopper but too slow. Carra gives 110% every time but both of these guys are a tad too slow and can't distribute the ball well enough. I hate to say this but see how well Rio Ferdinand intercepts and make good passes in the recent England internationals. This is one classy defender who also happens to be quick. We probably don't the money to buy a classy defender so we need to keep Hamann to cover our fragile defenders.