This is something the previous owner of my Eagle did that does help significantly reduce the outwards load on the hinges. The main bolts are too far back for the thickness of the metal and the load stress will doom them all to fail eventually unless you permanently close the hatch.
He drilled two new holes straight through the hinges and through the body and ran new bolts through. My passenger hinge is cracking, but it's old. After this fix was installed it looks like the fatigue stopped.
This is likely not a perfect repair for already broken hinges but it should go a long way to help partially cracked hinges from failing completely.