I also had that much better experience recently. There was a CX time and flight number change and CX just changed it. AS initially emailed me a few hours later (yes, later!) saying my flight had been cancelled and that I'd have to phone them and then a day after that another email said I was reconfirmed on the new flight.

However, subsequently the flight was cancelled anyway, so I contacted AS to change to next year. I tried online chat and the agent said that there was one seat available on the date I wanted but I'd have to phone to pay the tiny change in taxes. The agent I got on the phone couldn't see availability on any day in the last half of July for one of my sectors. Eventually, I got transferred to the international partner desk and they were able to see one of my preferred days but not the original one. However, by the time she had booked it, the original day had reappeared. (This was a couple of minutes over an hour after my original enquiry.)

The two main points I take from this are:
1) Keep plenty of time for contacting AS. While some AS agents know how to see CX flights, some still have no clue.
2) When speaking to agents who can find CX flights, the inventory exactly matched what I was seeing on QF and JL/CX. (Including the original day disappearing for an hour.) Really nice to not have the previous issue of CX holding back inventory from AS.