Because QF planned to use them on the high density Cityflyer route, they did not see the need for strong floors and higher engine ratings. Some airports in Australia charge the airlines on aircraft weight, not passenger volume so QF did this to reduce the airport charges. Good in theory but as noted before the A330-200 did not work too well on these short missions but better on the longer missions. I do not know where QF will put these birds if they are returned to the fleet. The trans-con routes now have more capacity amd demand with the aging 747-338, if they do take over from them will they get the Dreamtime seats and PTV in Y?
Trans-Tasman they have too much capacity, well according to the argument of QF-NZ

. Or they may have the floors strengthened for longer-thin routes which the new A330-200 are slated for.