I disagree with needing to play finals. Plugger didn't play a huge amount of finals, but is arguably the greatest ever full forward.
Good players have the ability to perform above the normal expectations.
Great players can win matches by themselves, and do so regularly.
Champions of the league, not only lift themselves, but also those around them, to higher levels.
In basketball, it was one of the criticisms put to Michael Jordan by the coach that ended up taking the Bulls to 6 NBA championships (Phil Jackson). He told Jordan he was a great player, but that he wouldn't be considered with the best because he didn't make his teammates better. Jordan took it upon himself to do that, because it was the one thing that seperated him from players like Bird and Magic Johnson.
For much of Richo's career, he was petulant, spoilt, and not a great teammate. He's come a huge way in recent years to changing this and set himself out as a leader. Unfortunately for Richo, I think when he retires, he'll be remembered by the football world more for doing the petulant dummy spits, the eratic kicking for goal and the dropped marks, than for his run all day exploits.
On his day, he's a great player. But he is too much of a confidence player, to be able to lift the average performing teammates to the extreme levels of their performance chart, the way a Wayne Carey could. Think, it wouldn't be too inspiring to be kicking it to a forward, who's either going to abuse you, give up chasing an opponent or drop his head, when things don't go his way.