Josh,
would C and E still cost about the same to operate when there is a great amount of VFR traffic ?.
I've answered your question in my previous post. With lots of VFR, C will be more expensive. Do not forget, though, that C is still required, because of the increased traffic, to protect against Midairs. I will hit a VFR just as hard as an IFR. Metal on metal doesn't differentiate between flight categories, as would occur in E.
In E with lots of VFR, I will probably hit one without knowing it and there are no defences against a midair apart from eyeballs out.
However, at Broome and Karratha, the VFR levels are low enough to allow C instead of E. If they get too high, then E is not the answer; a C with a radar (or ADS-B) is the answer.
The irony: with low numbers of VFR, E is not necessary. With high numbers of VFR, E is not safe (Ledsled if you don't get the context of what I mean by "not safe", too bad). Therefore, what's the point? The point is that E allows Dick and Ledsled to career through the airspace doing their own thing. That's all.