As a portuguese native speaker, I think Saramago is the only author (at least among those I know) whose books must suffer a very important loss when translated from portuguese to any other language, to the point it really affects the experience. The other authors you mentioned may suffer a little, but no one even close to Saramago IMO. I am not convinced of the exact reason for that, but maybe it happens because Saramago writes like our head thinks (like a deep and continuous thought) and that is more particular to a language than a text designed to be "correctly structured" and to make sense, as most authors do even in their native languages.