Regardless, the airframe of the F4 was a joke for engine guys and we ordnance types that had to drop the aft Sparrow launch racks every time they needed to change an engine.
After a bunch of combat flight hours, the airframe was so torqued we could not get the damn bolts lined up to re-install the racks. Hated that job, was never so glad to get out of fixed wing squadrons...............
If such a swing wing thing was considered, I sure hope a new aft airframe was part of the deal.
I worked on the F4C, D, &E’s never saw a B.. They used to come back with half the tail shot off.. Good Plane!!