I think the problem is mainly cultural: the Australian general public (like the americans) is used to high-score sports, they don't appreciate a well-played 0-0.

Unless you were born with it (like Europeans or South Americans), it's hard to understand. It's like cricket to me: I wasn't born with it, and although I've learned the basics and I don't mind watching 20 minutes of it on TV, you'll never see me on the stands.

Winning the general NRL or AFL public is a lost battle, it will never happen. But there is a whole new generation in Australia that was somehow born with football (along with the older hard-cores): that is the audience they need to target. And it will happen, if they don't screw it up completely.
How long is it going to take? Who knows...

I agree promotion/relegation doesn't make any sense at this stage: an expansion to 14-16 teams is a lot more reasonable. Canberra, Tasmania, Gold Coast (yeah I know...)
One thing we need for sure is a longer season, a 26 games regular season is a joke.