Maybe I am naive, but I really don't care who owns Qantas Frequent Flyer - Qantas themselves, some private equity firm, or some other group. The reality is that Qantas needs it to draw "loyal" customers to them so they will ensure whoever own it will manage it in such a manner that QF benefits most. And completely screwing all their FF members is not in QF's best interest so that won't be allowed to happen.
There may be changes, and some will be bad and some will be good - but the division of which are bad and which are good is likely to vary from person to person. The sky didn't fall in after May 25th 2005 when the last changes took affect.
As with most things in life, and especially so in the airline space, we have a choice. At any time if you don't like the QF FF program you have the ability to use a different FF program. There are plenty of options now for Australian frequent flyers who really are frequent flyers and not just frequent debt card swipers. Qantas has always provided about 6 months notice of major program changes, and I would not expect it to be any different in the future.
Anyone using an FF program like a bank account to save for the future (such as "I am saving for a holiday to New York in 2009") needs to take a fresh dose of reality.