Unfortunately, our defensive positions are full of players that excel in one area, be it pace, strength, tackling, passing, heading... But they fail in all the other areas.
Very much like our midfield of Davies, Gomes, Sigurdsson and Schneiderlin before Doucoure and Allan were signed. At least Doucoure and Allan are competent in most areas as well as the one they specialize in. Same can't be said of the defenders.