There's one or two things that need to be sorted before a red card system is introduced.
For starters, the competition is crying out for truly professional, high standard umpires, to remove the perceived bias, favouritism or unnecessary supporter scrutiny that currently exists, by ensuring umpire appointments are 100% impartial - a WA based umpire should never umpire games involving either WA team, for instance. This is a no-brainer, and common practice in, say, the English Premier League. I wouldn't trust the AFL's current crop of part-timers to make these kind of game-changing decisions, without some form of professional peer review of performance and sanction.
Secondly, the differences between Aussie Rules and say, soccer, ought to be considered. Soccer is a shorter game, played without an interchange. Accordingly, a red card has a greater impact on a team. A red-carded soccer player will often face criticism for 'having let his team mates down'. For instance, David Beckham foolishly retaliated against an Argentinan player in the 1998 World Cup and got himself sent off, for which he was publicly and mercilessly condemned. He even received threats.
The justification for bringing a red card system into Aussie Rules should be a focus on the need to redress the unfair disadvantage a team can suffer when a player is taken off after being purposefully injured by an opponent. And no, I don't buy the Gaff spin that he really only meant to push AB in the chest. With his fist. It was a deliberate and calculating action, which left Freo one man short for around a half of the game. The umpires should have been able to ensure that the Egulls also lost a player - Gaff. It's only fair.
