I think it would impossible for the union, with this situation or any other for that matter, to decide that longer paying members deserve better representation, or prioritised representation. In fact I think that in a lot of cases the more new to the job you are the more service you need from the union regarding T&C etc on a day to day basis anyway.
If we had to have the argument, I agree with Skywalker, a lot of the AO crew are ex Ansett and on that basis alone would give them "longer serving status". Having said that I don't think its a street we would want to go down. All members deserve equal representation and for my two cents worth I think they've done a good job loooking after all concerned under the circumstances.