Lookleft, you state in your post:
Transit through coastal CTZ should not be a rarity but denial of a clearance is always a possibility and should be planned for.
Lookleft, why should they be planned for? Surely you agree that if Airservices had changed the airspace back to Class E, as they had planned to do, and as mentioned in the ATSB report, the pilot and his passenger would most likely be alive today.
If you are suggesting that pilots flying over Class D airspace should do all their planning on the possibility that they may not get a clearance, that is something that would only be required uniquely in Australia. Surely we should follow world’s best practice.