I normally don't care about what happens to the A330 as it doesn't effect my part of the world, but in relation to all the A330's 'going' to AO consider this.
If existing AO / QF pilots are to crew this change in type it would require massive training costs.
I assume that most of the existing AO pilots will want to stay in CNS. Also most if not all of the current mainline A330 pilots will not wish to move to CNS.
Bare in mind also that there are two A330 basings, and the simulator is in melbourne. Presumably it would have to be moved also.
So if the 'aircraft swap' option happens, it is potentially not economically viable for existing crew members of both airlines to be used to fly the AO 330 operation.
The alternative then would be to bring in outside contractors - something the AO CP has expressed interest in in the past.