FYI: discussion on the a unified Australian frequency band for the public TTN network has moved to the Country → Australia forum category.
This would be the best to post to start from: https://www.thethingsnetwork.org/forum/t/future-strategies-for-au915-and-as923-in-australia/
If you are on Slack and interested in these discussions make sure your add yourself to the #Australia channel in the TTN Slack (get your invite at https://account.thethingsnetwork.org/.