I wonder if it’s not so much the airframe overall, but the landing gear and the reinforcement related to that? Even going as slow as possible, the landing gear would still need to be replaced with heavier stuff to land on a carrier, and the heavier gear in turn would probably require some re-engineering of the airframe.
I wonder if the real problem is a lack of space for the heavier gear, particularly the nose wheel? The GAU takes up a lot of room in the nose.
Also, the tail hook for an A-10 would have to be incredibly long, and I’d have to wonder if there is a risk of pulling the nose off the deck upon landing? The A-10 main gear is pretty far forward, the fuselage sits high, and there’s a lot of weight hanging behind the wings.
The tail hook for an A-10 would have to be mounted on the front, so the carrier could drive up underneath the A-10 and catch it...