I've noticed this as well, and my impression is that it's more about the Qantas boarding process than the aircraft itself.
Singapore Airlines manage A380 boarding at SYD quite efficiently. They set up 5 or 6 lanes with queue dividers and signage showing where passengers should line up. From memory, the left-most lanes are for Economy, the middle lane for Premium Economy, the next lane for Business, and the far right lane for Suites.
What really makes the difference is that SQ actively manage the crowd and avoid a scrum by having staff move through the queues and direct passengers to the correct lane (or to actually stand in a lane rather than dwell in the middle of the waiting area) when crowds start to form. Qantas may do something similar but without the crowd management (happy to be corrected if my recollection is off) which leads to quite the scrum at boarding time.
How many aero-bridges were they using?
I can't remember boarding a QF A380, but I distinctly remember boarding EY A380s on at least two occasions.
At both AUH & CDG they deployed 4 aero-bridges.
2 for Y PAX on the main deck and 2 on the top deck, for F & J PAX respectively.
On one occasion, boarding in CDG, I was booked on staff travel so I had no lounge access.
In desperation I had bought breakfast in McDonald’s.
Then the boarding call was early so I took breakfast as take away and sprinted to the gate,.
The door to the dedicated F aero-bridge had to be unlocked by an FA so I could board.
I was so embarrassed as I clutched my take away breakfast, I apologised to the on-board chef/sommelier.
He graciously replied "Monsieur, you can bring anything you like onboard!".
In AUH we boarded directly from the private lounge dedicated to PAX booked in The Residence.
We were escorted and we boarded last: the aircraft waited 15 minutes for us to finish our treatments in the spa!
Needless to say I was not on staff travel on this occasion. Staff cannot book The Residence.
I have another CDG EY F boarding story which I will save for another post.