The pins are not really the worst weak point here, though strengthening (enlarging) them can't hurt. The little bent sheet metal gizmo that hinges the mast to the base casting gets all bent out of shape just about every time your raise the mast. I still have not addressed this weakness, but I did replace the original stainless pins with Avibank (I think these are made by Hartwell) aircraft style quick release pins. Even though these are hollow and no larger than original they are made of a far stronger alloy and don't bend.
To fix the other thing I think you could make a step link out of solid stainless plate; I don't see any reason why it has to be made of bent sheet metal. Of course it would probably weigh half a pound but then you could always just leave it on the beach after you step the mast. You don't need it again until you take it down anyway.

Jimbo