I don't see why ATC could not have given a clearance direct to Bankstown with decent at the pilots discretion. Like all accidents, there are a number of factors at play here, any one of which could change the outcome. PGW needed what possibly may have been as little as an extra 500ft to have made the airport. You've got to wonder if there had been no requirement to descend to 2,500 ft whether it might have made the difference. The controller directed PGW to give up altitude it had no opportunity to regain for the sake of operational expediency. I'm not blaming the controller or saying it would have prevented the accident. Its just another piece of Swiss cheese that the report is deficient in not having examined.
Secondly, I said publish the questions, not the answers. Absolutely standard practice for qualitative research. Interview technique 101. It demonstrates an objective framework and allows peer review without compromising the confidentiality of the participants. Once again, not being across these techniques would question the authors qualification for the task.