The FFA Cup is a weird concept. It's definitely modelled on the FA Cup, but I think they've tried too hard to ensure that the fans of smaller teams remain interested to the end.
If you read into the structure of the competition, they've deliberately designed it so that certain teams can only be drawn against certain other teams - six A-League teams (out of 10) were forced into draws against each other in the very first round "Proper" in a deliberate measure to ensure that at least three A-League teams get knocked out straight away, and while some lower-league teams get cushy ties against the other A-League sides, other teams get put in a pool to be drawn against other lower-league sides. It continues that way all the way to the quarter-finals, with the FFA proudly announcing that there will be at least one lower-league side in the semis, since that team will have come from a pool which was guaranteed to face no A-League competition at any stage before this point.
This is where the whole thing seems a little silly to me - are you not guaranteeing that you're going to have one woefully understrength team in the semis? And how exactly is it fair on one team from the third division to tell them that they will only be facing teams from around their own standard for several rounds, and then tell another team in the exact same league that they must play an A-League team, and in all probability for the next several rounds as I'm not sure many lower league teams have the strength to beat A-League sides, especially since it seems to be the best-performing A-League teams who get drawn against lower league teams. Either you're denying a group of teams the chance for a money-spinning tie against the big boys, or you're denying a group of teams the chance to get very far, whichever the clubs view as being the more important opportunity.