Long term fix for Sydney is of course for at least one RW (34L?) to be cerified for Cat 3b
As I understand it, Cat 2/3 needs a TCH of 50' +9'/-2' - and unfortunately the newly-commissioned 34L ILS has a TCH of only 47'.
(You almost have to wonder if replacing the old 50' TCH ILS was done to deliberately preclude CAT 3 approaches...)