You need a breaker and a sweeper. One who is proactive and the other who covers.
Cannavaro- Nesta. Vidic- Ferdinand, Woodgate- King.
This is why we had some success with Fazio and Vertonghen. I don't think Jan and Dier will work until Dier fully learns how to attack the ball properly (also he hasn't been helped by Jan not sweeping up properly behind him.) Dier has been found out by Zamora, Austin, Costa etc in the last few weeks, but this is part of being a young defender.
Only the truly exceptional defenders are complete by 23.
Kaboul and Vlad?