Agree with T_C said, as much as I like Watto, its pretty poor form on his part to add pressure on a young bloke like Hughes, he has basically had three bad outings and already the tongues have started to wag.
I think the Aussie selectors have faith the ability of both Hughes and Katich, and that's probably the reason that they didn't think it was necessary to have a back-up opener, because they probably were/are willing to persist with both Hughes and Katich right through this series.
I can understand Watto's frustration in the current scenario, but he needs to stop trying to be the jack of all trades, he was picked in the squad as a middle order batsman, and had his body not betrayed him, he might have even played in the first two tests as a middle order batsman, but that was not be, and now he would just have to patiently wait for his chance to come.