This is not the point.
One more playmaker doesn't mean he should always be outside the flyhalf!
What makes difference sometimes, is when you have split the field, with 2 sides where attack, and sending a good playmaker (12) to one of these sides, he must have good hands, sharpe boot and should be a decision maker.
Once he is outside Cooper, he can be skipped with some movements that put others in space...
Wallabies need this kind of player because they have a open-style game, with dynamic forwards and very talented backs capable of reading each situation, they don't need pure crashing-power among the backs (but they need it in the forward!! where they really lack of)!
"Penetration" means to pass the defence line, not necessarly to go straight into it and win the collision!
The best games Australia played in 2010, have always been played in this way, with these kind of players. Look at vs. France, vs. All Blacks in Sydney and HK, even those strange games played in the highveld against SA: great tries were scored by backs running different lines, 2 or 3 passes, no more, but well executed and great decisions taken by playmakers, QC (10) or Giteau/Barnes (12).
When QC were involved in rucks or tackled (or they just got switched), there were someone else to take stand-off duties and deliver the job:
Ashley-Cooper vs. France, Ashley-Cooper in Hong Kong, Drew Mitchell in Hong Kong, Drew Mitchell vs. SA (Brisbane and highveld), O'Connor vs. SA...
This is (or at least has been) the most effective Oz backline combination. There are no doubts about that.
And let me say Beale can't be the outside playmaker, because he is a NATURAL talent in the open spaces, this has already been spot by all media and forums, his great capability of counter-attack, finding spaces in broken play are the biggest reason he's the best option at fullback for Australia.
And the best fullback in world rugby.
If Beale should be involved in the tight stage of a phase, near to the rucks/mauls, he will lose 50% of his efficacy!
He need to be involved in plays after n.12 and even after 13 if blindside wing will come into the backline!