Could it be that some are missing the elephant in the room?
Ambidji indicated that the 'risk was intolerable when compared to the CASA risk criteria' (paraphrased).
If the actual experience of operating Bankstown and the other GAAP airports for the last 30 years shows that in practice, accidents and serious incidents are not occuring as forecast by the risk model, then mabe, just maybe, CASA's risk model is wrong.
Dick - maybe rather than getting a bunch of non-aviation, but still academic and Australian, types to look at the Ambidji report, it might be better to get the FAA to do an analysis of Bankstown against the US criteria and settle the matter once and for all.
They could model Bankstown as a GAAP airport - and then as a US style Class D airport.
I don't propose you fund it, but surely CASA could seek FAA's assistance. At the very least it would expose some of CASA's risk gurus to world's best practice.
It might also be useful to get CASA to send their risk model to the FAA for evaluation and attenuation.