Cozart had the 12th best OPS of all SS who played the position and went to the plate enough to qualify in 2012. Three of the guys ahead of him were Hanley Ramirez, Starlin Castro and Johnny Peralta. Three guys I wouldn't have as my SS were I king. Those three guys are 3B or maybe CF playing a position they really can't play very well.
I know Cozart doesn't hit much, is mostly a lefty killer and has a low OBP, but there just aren't many SS who can do the job and hit as well. As guys like that go, Cozart is better than a whole lot of other options. I don't like him hitting second, but I don't think you'll find many better SS around. Probably can count on one hand guys in the NL who are better. If Ludwick doesn't get hurt, Phillips is hitting second and no one is railing against Cozart. Dusty just doesn't believe in moving everyone in the order up and letting his best hitters get the most PAs while his weaker hitters sit at the bottom of the order. As a result, we get a revolving door of Heisey, Cozart, Izturis, and other weak hitters filling the spot between Choo and Votto.