I can't speak to Leibniz since I haven't studied his philosophy at all, but there seems to be at least a distinction between a fallen world (or a corrupted worl

I can't speak to Leibniz since I haven't studied his philosophy at all, but there seems to be at least a distinction between a fallen world (or a corrupted world) and a fallen man. That is, you could take the view of some (so called) gnostic sects that see the world as a corrupted mess created by a demiurge. In such a view one could understand man as a divine spark that is imprisoned within this world, perhaps even maliciously tricked by that demiurge, and gnosis is the realization and means to escape. That is a kind of heresy that was argued against quite vehemently by the early church fathers (as well as Neo-Platonists like Plotinus for what it is worth). That would be opposed to a view that the world is a good creation (or at least as good as was possible given the material available, in the vein of Plato's Timaeus) and man is the ambiguous thing, given free will and the choice to align itself with God. In that case, the fall of man is better seen as a rejection of a good that has been offered.