He gets caught flat footed and is on the wrong side of the ball/too tight too often. I don't think he's irredeemable, but there's little time left to humor those really significant failings for a defender, even with his age. The thing is, when in position, he's a good defender, good tackler, tidy in the ball, doesn't get nervous in possession etc.
I tend to think we'll be seeing more Aurelio in the near future.