For those who may be interested, here are some findings from the JOINT CASA AND RAAF AERONAUTICAL STUDY OF WILLIAMTOWN AIRSPACE October 2015:
"The unique circumstances of Williamtown prohibit the safe use of Class D services due to: military flying operations, geographical position of the aerodrome close to coastal VFR traffic, and lack of separation services. The annual number of passengers already meets the thresholds for at least considering Class C airspace and services. Under the Civil Aviation Act 1988, CASA must regard the safety of air navigation as the most important consideration."
"The study considered all operations in the vicinity of Williamtown and the current and projected passenger numbers and concluded that Class C airspace would provide the safest and most efficient service for Williamtown."
"A coastal VFR route will be required with any airspace design due to the proximity of the aerodrome and its CTR and the need to protect aircraft in controlled airspace and RAs. The study team concluded that a VFR procedure such as Sydney Victor One is not compatible with an ICAO based CTR design for Williamtown."
https://www.casa.gov.au/sites/g/file...f?v=1444362227