While I think it is "plausible", I'm only seeing a one way compromise. I'm quite certain the FST cars are not going back to drum brakes and link pin beams, a 1200 motor, or a VW worm gear steering box1. Wheel base can be up to 2" longer
2. Body length can be 10" longer
3. 1600 engine. Mostly stock , but with allowed aftermarket parts and a FFDA provided restrictor plate and W-110 Cam. Develops about 85HP (100+ lb ft torque)
4. Mandatory stock VW transaxle with long box and 1.26 third gear.
5. 4 Wheel Disc brakes
6. Ball Joint beam with certain allowed mods.
7. Aftermarket wheels (13" x 6") with the Formula Ford Spec tires. (Hoosier R-60A)
8. Weight 1125 (with driver)
9. Rack and Pinion Steering allowed.
10. FIA F3 cockpit opening (no fan shroud rule)
The "compromise" in terms of bringing the cars closer together in specification is a slight possibility starting with disc brakes and BJ beams. We could allow an additional 2" wheelbase for those height challenged individuals that wish to add some cockpit length A rack and pinion would not be a class killer...
Weight's not going up. Wheels and tires, not going to happen if it slows the cars down IMO. I think among many issues anything that slows the car down has zero chance of approval. And there is plenty of opposition to brake/BJ beam changes, but I think it is at least possible.
So, while I voted plausible, I think it has very little chance.
Barry