Problem with Cooper is that he generally holds the ball in two hands when attacking the line. Actually it clearly isn't a problem as he is always ready to give the pass. The real problem is that the ball, even in contact stays in those two hands and away from his body, he is always looking for the pass. It is what leads the ball to be turned over when he is tackled. He can't secure it tight enough, particularly if he falls on the wrong side.
It is both good and bad, but he still has some learning to do.