General broadcasts during adverse weather
SF thank you for the compliments on service delivery. This is important for controllers to hear, as it keeps their professionalism bar at a higher level when they know what aircrew prefer.
"All stations, be advised Shenzhen is no longer accepting diversions"
I'm aware this information is useful, but it can be quite impractical to track accurately. Diversions to airfields with limited capacity such as Macau, could change minute by minute. For this type of information to be passed on operational frequencies as well as status updates on HKIA during adverse weather could easily create a safety just with managing separation of aircraft. If it were some definitive information such as an aircraft disabling on the runway in Macau and there is a prolonged outage, this would be possible.
While 'general broadcasts' are very efficient means of distributing information they are not a complete form of communication. That is, there is no read-back from individual aircraft that they have received the information. 'Say agains', more detailed explanations and aircraft acknowledging can rapidly saturate available talk time. This could easily lead to ATC loss of control of the situation.
I would think such information is much more suited to being data linked to the flight deck. There is a package of Collaborative Decision Making (CDM) that is being developed for all stakeholders at HKIA. This type of information should be available to Airline Ops Centres, just as accurately or as up to date as ATC has, via such a medium. They could prioritise it accordingly.