Richmond would not be acceptable because of the towns on each end of the runway - Windsor and Richmond. They bleat enough about the mil planes, they will scream their tits off if civil jets started using it.
Runway can't be extended, disappears in fog fairly regularly.
Wherever some political drongo wants to put it, other drongos will start their nimbying.
It will never be built anywhere near Sydney, because no political party has the spine to do it.
Bring Jeff Kennett to NSW and see what happens.