An interesting little exercise will be to look at the nights where there was chaos at SYD and they have 10+ departures post curfew to see how many noise complaints were generated. Personally I think there should be a curfew but they need to reign in the current system. This business of flying for 15 hours and then diverting interstate to sit around for 8 hours to then fly back to Sydney needs to stop.
If they can actually build the new West Sydney Airport it will probably be the best solution for all. At least carriers can divert to an airport in the same city.