Jack Newton raised exactly the same issue ahead of the last Open at The Grand. For what it's worth, his rota comprised
Royal Melbourne, Kingston Heath, Metropolitan, Huntingdale, The Australian, Royal Sydney, Royal Adelaide and Lake Karrinyup. Of course, given the work his firm has done at Huntingdale, he never misses an opportunity to talk it up.
Somewhat controversially, he said that the Open should never be taken to Queensland because of the Bermuda greens. I would imagine that newer courses up there such as Brookwater and The Glades will stick their hands up in years to come
Chris, if they could just add some length and some strategically placed pot bunkers, I am sure that Commonwealth would earn a place on the rota. If only they had let Hartley realise his vision on the rest of the course. I also believe that your favorite golf writer, Tom Ramsey, believes that there should be no rota at all, but it should be held at Laguna Quays every year.