Because I don't think his technique is particularly flawed against pace bowlers, I think his temprament is, and they are different problems. Hayden and indeed Ponting have fairly poor techniques against pace bowling. Both make up for it by being unbelievably strong in their strengths (Hayden's drives, Ponting's leg side shots, especially pulls) and having good mental application. Clarke has superb footwork, and is generally quite organised against pace bowling. He's not as good as say Watson or Blewett technically, but he's not anywhere near as flawed as people make out. He does however lose concentration terribly and do things which appear to be technically floored, like failing to get behind the ball, and playing with his wrists well away from his body and his head in the wrong position. He doesn't do this all the time however, and if you watch him when he gets a start, like many of the 30 odd scores me made in the Ashes, he really looks very good most of the time and then has a lapse.
I think he's definately worth persisting with for this reason. His Ashes series was decent (not great, but not a droppable series either), and I think he should be left this season at least to see how he goes. If his mental problems continue, fine, send him back to NSW for a while, but he's not been a dismal failure and he has heaps of potential, so I support his inclusion for now.