Dick,
You're not making sense.
The reason these countries have E over D is so that the Controller – often a lone Controller in the tower – can concentrate on where the collision risk is greatest.
So when the weather is bad, 8/8ths from 20k to the MDA, you've got your lone tower operator doing the whole thing. E and D. Or is it really the centre controllers running E, so your comment "can concentrate..." is meaningless.
The reason the USA and Canada have E over D is not to provide access for VFR
Pull the other one, mate.
considering that so few VFR aircraft will actually fly over in the broadcast zone,
Well, I'm glad
you've done a CBA on this. Given so few, then why on earth is the zone not being taken up to 4500ft? The workload will be the same, unless you are going to pay for the upgrade of the Centre controllers to become approach-rated to hand off IFRs to the tower in their tiny CTR.
So you've answered. You're quite happy to support a bodgied-up, confusing, non-standard airspace design just to get your fabled E in. No VFRs in Broome you imply? That's why the tower is going in, old chap. There aren't 100 jets a day there. The Broome VFRs are quite happy with D, by the way. It's only you NAStronauts who might fly through there once in a blue moon, or bleated about changing the steps into Alice by 2nms, that are the problem. The fringe running policy. Excellent.