I think Piere is suggesting an increased ATZ size rather than a new form of airspace.
The trouble with this is that an ATZ might as well be class D as I understand it. One there is full ATC there, then you require their permission to enter, and you must follow their instruction once inside. Not much different to class D.
where they have no more protection than the local flying club.
You never mentioned who "they" are, which in itself makes it obvious that you see this from the airlines point of view.
An alternative point of view is that the airlines should operate from the regional airports with the protection of controlled airspace. If they choose to operate from smaller airports without the protection of controlled airspace, then that is their choice. They do it to save money and increase profits, and they shouldn't expect the rest of us to pay the price for that, by suffering further regulation and delays.
What if each airline decides to operate from a different airport, to get a better deal than their rival. Do we end up covering the whole country in controlled airspace for the same fleet?
dp