Since I've been working class D control zones with class E terminal areas, I can only say that it works really well.
You'd still get traffic information in the control zone, and the terminal area (if we're aware of any aircraft there communication/coordinated/transponder). And we'd keep the VFR away from the arrival paths of IFR flights (final/departure).
The problem with G airspace, is that VFR can fly just under the clouds, no transponder, no radio, giving the IFR guys comming in on a localiser a real hard time to spot him before it's too late. The D airspace relieves the IFR flight of that in a critical phase of his flight.
I do not think class E is good enough for a control zone though?
What otherwise can be done, is establishing a traffic information zone, where the class is G, but radiocommunication is required, and man them with aerodrome flight information service. That'll give better protection close to the field than no zone.