There is more to literature than storytelling, and Brandon Sanderson lacks it. That doesn't mean anyone is trying to imply you should be ashamed to like Sanderson or for having your own criteria for judging books, but "fluff" by definition means "lacking depth", and as I said before, Sanderson himself would not try to argue that he is writing books that are supposed to be "deep". Both Dickens and Dostoevsky wrote profound novels that will be discussed by educated people for centuries if not millennia. It just takes a bit of effort to appreciate them, though it is well worth the effort.