Interesting that they now have a disability queue along with families
I know parents of extremely rambunctious boys would be thrilled to avoid long queues
The disability queue at SYD is at the same end of the terminal, but has priority over families for both security and immigration.
The family queue is usually quite slow and long. Security is insufficient - there are only 6 'bays' to load carry-on baggage for x-rays which are shared with the disability queue. As you'd expect with families, there are plenty of infrequent travellers who are nervous, stressed, or simply have no idea what they are doing. There are also lots of liquids being carried on for infants, which slows things down at the other end of the x-ray belt as they need to be manually checked.
Once through security, the manual immigration queue (required for under 8s, those under 1.1m tall, and those in wheelchairs) usually only has two or three agents working, and often has 30+ families long. The disability queue also shares these agents and gets preference over families.
My wife and I fly with our two year old quite a lot - her logbook is up to 52 flights. On a good day, immigration and security at SYD seems to takes about 30 minutes. During school holidays it is often closer to an hour.
Probably the most annoying part is they won't let us use the J/F priority queue even when we are flying a premium cabin!
We took the family line, but at the end were funnelled into the normal queue, so I'm not sure what the point was.
Kids under 8 and/or under 1.1m tall? The normal queue is far quicker anyway.