I think a lot depends on what motivates players to make a move to the Antipodes. Others have commented on that already for example that for some it could be "resuscitating" their career stalled through injury (Hooper) or by lack of exposure (Davila).
But what I do not know is what motivates locals (AUS/NZ) to come home from Europe while still in their prime. So I am less interested in the reasons why McDonald might be back in HAL (first WU now Roar) as he is still a very good player but clearly in the later stages of his career. I am more interested why someone like Marco Rojas would choose to come back to HAL when he is still in his prime.