Stubby jumbo: it's actually a 1010 departure SYD and an arrival into PER around 1300 LCL. The 744 then departs PER around 1435 and arrives SYD 2020 LCL.
Given all the A330 and B767 flights both earlier and later in the day, what exactly is the problem? You want a later 744 departure out of PER and have the plane end up in MEL or BNE because it's missed the SYD curfew? One of the eastbound flights has that problem every day - you want to simply switch the types around? Or are you wanting the 744 Skybed on the redeye PER-SYD? That would be nice but the skybed is not really targeted at 4 hour sectors. You really have to consider where the Skybed is wanted at night: coming overnight into Aus on long sectors from HKG, SIN (ie Europe) and from the USA. So it really isn't as simple as it seems.
A look at June's timetable shows 7 QF flights doing SYD-PER-SYD, all at different times of the day, to meet demand throughout the day no doubt. Perhaps putting all that extra 744 capacity on in the middle of the day means that now business class pax won't be struggling to get a J-class seat on any of the other 6 flights!? Greatly improved flexibility for the suits!
There is just no satisfying some people though.... We could bring caviar back onto the menu and no doubt you would smell something fishy in that.