Is it just me or is there a fixation with lines in the sky as opposed to good practice? The IFR traffic will be in controlled airspace (E) so will still call where they do now. If you were operating VFR that day or were a VFR visitor why would you wait until 8nm to call the Tower. (Just because you can!)
Let's imagine for a moment that there is a Tower but no lines or airspace designators, what would a simple man driving a plane do?
I suggest he would call (VFR or IFR) at a distance commensurate with his speed and expect circuit joining instructions. Remember GA airports?
If he was overflying he would call at about the same time, tell the Tower what he was doing and wait for a response. He would also expect the Tower to exercise the controllers duty of care and direct him to fly in an area that was not going to be used for circuits and approaches.
So now lets throw in a few circles and lines just to let pilots and controllers know the limits of the different service areas. (ATC gives different services depending on the airspace classification). With the addition of these few lines why has anything changed? We all still know we have to give the controller time to find out where we are and fit us into his mental picture, why does the position of the service delivery line (aka airspace boundary) make any difference?
The E broadcast area above D is there because CASA and our airline colleagues do not believe that GA pilots can be trusted to apply commonsense to flying procedures. Why do we continuously impose lowest common denominator rules instead of expecting higher performance and common sense?