You could obviously start the season 3 weeks earlier (keeping in mind the Oct intl break) to remove the need for midweek games. What is the hard limit causing the league to start so late? Stadium availability, or broadcast arrangements, or what? Could this be sorted out in the next broadcast deal?
AFL Grand Final is 27th September.
NRL Grand final is 5th October.
6th - 14th October is a FIFA window.
So if you start early, you are going up against the climax of the winter codes & then head into an international break. By starting after that international break, the idea is that you have some clear air in the media space to promote the start of the season.