The problem with mediation through Legal Aid and Relationships Australia is that it's often perceived as the cheapest way to get a s60i certificate so the more expensive, but also more serious, process of court can begin.
Realistically, of course, the success of mediation comes down the participants, but it's often the case that if you need a mediator, the conflict is high enough that agreement won't likely be reached. Both parties need to have a genuine desire to reach agreement, which means negotiating and compromising. If one party is set on it being their way or nothing at all, mediation will fail. If one party is convinced they will get what they want from court, mediation will fail. Unfortunately, it often doesn't matter who the mediation is done through, if the attitudes aren't right, it will fail.
In a perfect world, separated parties could attend conciliation, which is where a court authority (registrar, for example) delivers judgement on face value of the case, without having to go through that two-year process of court deliberation, testing evidence, interim hearings, etc. In an even more perfect world, parties would be obligated to attend a post-separation parenting course or child conference before commencing proceedings, so both parties are clearly informed of the studies and evidence that shows how their behaviour impacts the kids. Most parents don't realise (or perhaps refuse to acknowledge) the court doesn't tolerate parents who withhold time, who denigrate the other parent, who don't know that focusing on the negatives of the other parent is more destructive to a case and a child than focusing on the positives of the other parent.
But these resources don't exist. Parents are expected to know all the consequences of their actions already, despite being first-time parents dealing with their own emotional trauma at the same time.
Anyway, that's my view. Fundamentally, both parties need a desire to reach agreement. If that desire isn't genuinely there, agreement won't be reached.