Perhaps in a key game you revert back to playing with a backup keeper?I see where you are coming from however if you have players like Reid on the bench he can play in 3 positions well you should have enough with four subs to be able to change the game?
If you have a bench of Robinson, Reid, Revell and Butters that pretty much has everything you need.
You are right about 99 out of 100 times not needing a keeper but sods law is such that when it happens its a key game.