People seem to overrate defenders becouse they played in LaLiga, which doesnt have the best defensive play to start with.
Pique is good if he jsut gets his act together, which he havent done the last 2 years.
Bartra is not a world class starter CB yet, and i dont see him becoming one either. LaMasia doesnt equal future star.
Mathieu is below mediocre if you look at top clubs in the world and 30 year old.
Vermaelen is not even close.
Mascherano has 0 awareness and only looks at the ball. Really bad at man marking.
Our central defence is very weak still if you compare to other top clubs.