Yes, it's a well known point that it's one in one out without a tower. You CAN do Class E without surveillance with a little better than one in, one out. The other point is that you CAN'T have a tower at every airport but you CAN have Class E.
I'll say it again, Aus controllers, through no fault of their own have not been instructed or educated in how to use Class E effectively. The liability laws as they stand in Aus will NOT support Class E.
Half arsed Class E is pointless. Either E base 700ft or leave it Class G. E Base 6500 is dip****tery.