i really dont think its a matter of havin a plan B.
Its just that their basic plan has many variations.
when Hardwick took over there was a lot of banging on about the new simplified game plan, but i think many missed a subtle but important comment by Reiwoltd at the time . he said going from wallace to hardwick was like going from primary school to high school.
For the first time in their career the players were given play books with all the set plays and their variations to learn.
I also dont think predicibility is an issue. In modern sports everyone pretty much knows what every one else is going to do. The better sides just implement it better than their opponents. Very few game are actually won or lost by the use of some surpising tactic out of the blue. As hardwick pointed out when he took over, everyone knew how the geelong team of the time played, they just it so well they were hard to beat.