I find this somewhat hypocritical when you dismiss any AA in Scotland bar those playing with Celtic or Rangers.
Belgian league plays a different style of football than many Scottish teams. There is a lot more depth too - given their high UEFA ranking.
Ditto Italy's Serie A.
Miller is improving in Scotland. He may be the exception, not the norm. In a some facets of a player's skill set, some Aussies playing in Scotland are stagnating, compared to those playing in other UEFA leagues outside the Big Five like the Championship, League 1, Belgium, Netherlands, Austrian Bundi, Denmark, et al.
Not sure if you've heard it, but I recommend the excellent G and G Podcast 15 where Bulgarian scout, Peter, is interviewed. He knows the Aus football scene well. Grazor, the host, asks Peter lots of questions discussed on here.
Peter is a former pro footballer too. He states that Scotland, outside the Glasgow giants, is similar standard to the AL and English League 1. Peter contends that the AL and L1 are more technical than Scotland, with patient build ups from the back. A national objective from the national football fed in Aus.
Not just me saying this but an objective pro scout, familiar with a wide range of countries in international football. Peter also states that our Squeezing and Pressing is less intense in the AL, hence players have a bit more time on the ball in the AL.
Grazor poses some excellent questions in G and G Podcast episode 15, as he does in 14 and 16 too. The G and G Podcasts are becoming an invaluable resource. I've learned a lot!