Australian here. I would complain about this article being inaccurate, but it's probably more accurate than most of the actual Australian reporting.
Without going into too much detail, this is just an in principle "Maybe we'll allow an R18+ rating" between the state governments and the federal government (New South Wales abstained.) Nothing legally binding and definitely nothing that hasn't been hinted at before. Gamers have a history of readily swallowing the bullshit spewed forth on this topic.
Other complicating features. The OFLC (classification board) is in the middle of making a power grab to enable far more censorship of all media, the R18+ classification for video games is no guarantee that things will be better. The South Australian government has also hinted that they may turn the existing MA15+ rating into the R18+ rating, enabling no currently banned games to be unbanned.
Video game classification has only been around 1994 (around Mortal Kombat/Night-trap time). It is a myth that this is something that publishers have always had to deal with.
Another Australian here, a games "blournlaist". Actually most of what you've written is wrong. It is not a "maybe", the Federal Government has overridden the "no vote" by NSW. R18+ no longer has to be discussed at SCAG meetings, it can be done outside of this now. Each state can implement the new guidelines without having to wait for NSW, who has only been in this position since April.
The OFLC hasn't been around for 5 years - you mean the Australian Classification Board. They aren't making a power grab, its about seeing what needs updating, fixing some old guidelines and bringing them in-line with other mediums. Have you read the proposed R18+ guidelines at all, what makes you think it wont be better? It fixes up a lot of the issues and also allows adults to play adult games.
South Australia not enabling currently banned games to be unbanned??? All states wont allow this, not just South Australia. Previously refused classification content would probably have to be resubmitted for classification to get a rating.