If Australia played a similar level of cricket, they would have beaten any team in the world 5-0, and in fact would probably have hammered a number of them even worse. South Africa toured last year and Australia didn't play half as well and still won 5 of the 6 tests, so I don't see why they'd have managed to win one.
Obviously it depends a bit on individual performances, but realistically I don't think there's any way you could predict a score other than 5-0.
I know a place where a royal flush
Can never beat a pair