The type of activity you described led 35 years ago to formally issued FAA policy that prohibits approval of revenue "flight with cracks" for primary structure or fail safe features, although some inspectors or offices may not consistently follow the formal policy. The AD program for the pickle fork fitting undoubtedly will continue to involve monitoring for cracks beginning at some threshold, with repetitive inspections, with the intent of providing multiple opportunities to detect the cracks before they can go critical. However, once any cracking is found an appropriate repair or replacement will be required. In this case nobody has yet identified a practical and effective repair scheme, so replacement for now is the corrective action once a crack is detected. Since the NG is out of production and the cracks seem to appear later in the life of the airplane, Boeing may just stick with the existing design and live with the potential for one replacement required in the life of an airplane. I have not heard anything about development of a redesigned fitting, but it's possible one is in work.
I'm hearing rumors that cracks have been found in adjacent locations on a few airplanes ...