Saramago developed that style in his second novel; if you're not taken with it by now, you'd better just give him up
honestly, I love his work, I don't love any other contemporary writer as much as I do him, but I doubt you can't find more writers who say the same and write in a traditional manner.
Blindness didn't presume to reveal anyone the nature of Mankind; Saramago speculates on how people would act in the fantastic situation of universal blindness. If Saramago doesn't portray Mankind positively, it's because he's a 84-years old and has lived in a century in which it's difficult to be an optimist. Even so,
Blindness's darkness is regularly counterbalanced with unpredictable moments of Love. For that matter,
Lord of Flies has a far more over-the-top view of human nature. Unlike Golding, who stuck with DARKNESS for the rest of his career (don't fix what's not broken, if it worked with one novel, it works for ten more, hey look, they gave me the Nobel Prize for Despair), Saramago usually has a lot more to say about Mankind than the usual doom and gloom. But unless you read more, you won't know that
I don't know what to make of your point about structure; it seemed conventional to me: event A leads to B, leads to C, leads to D, etc., all the way to Z. The End. It was in fact one of Saramago's most straightforward plots.