Hmmm,
well let me add my 2c.
Coming from Germany I can tell you it is Way too easy to get your licence in Australia.
Over there you do Freeway driving, emergency braking, wet weather, night time, all road surfaces and general maintenance and mechanics of a car over at least a years worth of lessons. It's an involved (and expensive) process but means that you actually have a clue about how to drive (you'd want to with the Autobahns and all ;-)
So the biggest problem is not the cars but the training. Add to that the fact that Australian roads are in a pathetic state of repair and the fact that cars do not need an annual road worthy check over here and you get a fairly good reason why things are the way they are.
If you fix these issues you won't need to limit the cars. That is just a 'knee jerk' reaction because everything else is too complex for the simple minds in Spring Street (or Canberra for that fact)
As an aside I am now in my late 30's and only now feel confident enough to consider buying a GT-R ;-)