Looking at recent Socceroo games, it seems like the MLS in the US, the JL in Japan, and the English Championship, are improving as good options for Aussies, who don't make the Big Five in UEFA, or, the 30 odd big clubs in UEFA who play a lot of Champ League or Europa League football in Netherlands, Portugal, Belgium, Switzerland, Scotland, Greece, Turkey, et al.
The Aus players playing in USA, Japan and English Championship, have developed skills that are extrapolating well to international football. These leagues may well be increasing their world ranking in global football - and - are becoming better destinations for prospective Socceroos.