Yeah SYD is a real pain. Considering so much work was done to the airport for the Olympic games not so long ago.
It's (to have one airbridge) a very egalitarian notion considering Aussies have embraced the elitistism of travelling so readily. Just look at the QF board & all the discussion on upgrades, lounges & other elitist aspects of air travel.
The airbridge sitiuation at SYD may change as mentioned below with Qantas' new A380 Airbuses (delivery of which is delayed) so maybe CX will benefit but I suspect all aircraft except the A380 will stil get one airbridge at SYD.