I don't really mind his tactics of staying back. I mean it is his game style, he's more likely to return 1st serves and has more time to play his shots and move to the ball. He's quite good at counter-punching but can also generate lots of power from the back as well. He doesn't generate spin so coming forward is not easy for him.
The problem has been that he makes too many errors, as we saw today. He looked very lazy, compared to Hopman Cup where he was serving aces at will, moving so fast side to side and returning very consistently.
I was definitely not impressed by his performance today.