Until about two maybe three years ago there were NO QF international destinations from Perth
I must have been dreaming then when I operated SIN/DPS/CGK/HKG/NRT as late as 2010 then....
As for T1, the '2 flights of stairs' on departure is the same setup it was when I was 10 years old... which was in the 90s. It literally hasn't changed structurally since, just new carpet (that still smells)
A least for departures they upped their game with the ramps but boarding is very slow especially with a full A380 going back to DXB