JQ wont take over QF. JQ is a low-cost model that quite frankly is doing very well for itself. It's had support to get going, it gets aircraft given to it, but the 'brand' is far too established both domestically and internationally to ever be morphed into QF.
I'd be more concerned about Cobham and their business class fitted 717's operating on the east coast. Don't forget, QF domestic has been split from International and therefore is not bound by the QF sales act or its protections.