DM, when I say that QF Link is a premium product, I mean that it is more akin to Qantas mainline service than Jetstar or Ryanair. In many regional centres QFLink get the high paying passengers who will expect to earn FF points, get something to eat, and also are more brand loyal to Qantas. They would lose a lot of brand support if they changed them to Jetstar services, given that Jetstar is not a great brand. The beauty of Qantaslink, particularly on the East Coast is that it often feeds in to services on the wider Qantas network, as well as being highly profitable for them.
I would say that Jetstar will take over some services, but that the Dash 8s will still have Qantas badges on them and probably still be operated by the various carriers that make up QantasLink. To re-brand the whole things as Jetstar would be marketing suicide for the roo.