His technique isn't good enough against the moving ball. If you look at how he stands before the delivery is pitched, his chest is usually facing towards mid-off and sometimes even closer. He gets squared up much easier than he should, and it doesn't help when he has no footwork.
In the past, he used to move his feet well and that would prevent him from squaring up, but the lack of runs and confidence has reduced that as well.
In England, he was prone to nicking the ball in a particular length after getting squared up, and Australia exploited that as well. It might have been that he tried to fix that aspect by being aggressive at balls outside the off stump, but it hasn't worked at all.
He needs to go back into domestic and get his bearings right, because the last thing we need is a walking wicket.
