The difference with BA Europe services which have the dodgy seats is that you can purchase their business class online (with restrictions) at greatly reduced prices off the full fare - eg travelled Gatwick-Malta for 70% discount off normal business fare.
And you still get the full mileage and SCs if you are QF FF.
With QF avoid the early 737s - typically on the SYD-CBR, DRW-CNS, BNE-CNS, BNE-MKY type routes where possible.
Best option domestically to get the best seat is to travel on the domestic leg of an international flight (eg SYD-BNE, SYD-MEL, CNS-SYD, etc)
Occasionally you get an international 767 doing a domestic - eg QF 707 from CNS-BNE uses the 767 in from Japan and loops it to BNE and back to CNS as a domestic flight - the aircraft is towed betwen the terminals in Cairns.
Next choice 737-800s and 330s, newer seats, a little cramped
The seats in the older domestic 767s (eg running the SYD-MEL route) are pretty tightly packed and old now.
The older 737 seating is at the bottom of the pile - but at least there are only a couple of rows of business class (unless on SYD-CBR).