Interesting points
777.
One could also wonder if their domestic FF program would be as strong if the incentive of alliance-wide status was removed.
For the domestic-only flyer, it wouldn't really make a difference - though for me personally, being able to earn points on obscure (and shorter) routes around the world is a huge incentive, as it all adds up. While long-haul partnerships are great (EK), other airlines that QF aren't particularly friendly with still offer a great advantage when considering their hubs' geographical location, including BA, MH and CX (and, to a lesser extent, AY). If QF were to go down this route, I honestly can't see them keeping the first three on board in the same capacity (if at all). That would have me seriously reconsidering my domestic flying loyalty, as VA would then have an advantage with SQ's hub, likely leaving QF with JL as their primary Asian partnership.
All speculation and opinion of course (and perhaps drifting a little O/T), but QF leaving oneworld wouldn't just shake-up their international network.
IF EY were to join, QFF could then become the program of choice for residents of the Middle East, as flyers could then pool all their points and SCs to the one FF account from EK*, EY and QR (and the remaining OW airlines), and likely achieve status quite quickly across a very broad range of airlines. It'd seem like an advantage for QF to maintain the OW membership and for EY to join, but that's just my opinion!
*Provided that QF codes were booked
I probably wouldn't have said the same thing when I first heard about the invitation though!