Re FAA:
The FAA usually acts (and has done so in the past) mainly as supporter of the American Aviation industry.
If this requires improved safety measures by the industry they will act also in the interest of passengers.
If there is a conflict of interests between safety and the interest of the industry, that's when it gets interesting...
In the past not always (to put it veeerrry diplomatically) safety has won in these cases...
The loophole certification of the S-92's MRGB unfortunately fits perfectly into this image.
Someone high up the food-chain in FAA should have lost his job over this. But I'm afraid you won't see this happen.