I like the current setup with 4 games, 2 home and 2 way, against each team.
With 9 teams, we'd get a 32 game regular season, and I think that;s fine.
We often play 2 games a week, so its not like AFL where you need to worry about byes.
At ten teams, that would be pushed to 36 games. Whilst that's not huge by international standards, it would start to push the length of the season and venue availability, especially in Melbourne with two teams and the Tennis.
Anything more than that, and we'd definitely be looking at un-even series, probably 3 games against each other team.
We've had it before, and if needs be it will happen again, but people will whinge if team A finishes ahead of team B because they got 2 home games.