I am not sure about this question but I have an idea. The perfect author is the one that you can understand well or produces this sense.
There are two reasons for not being comfortable reading a work. One is the author love to use many words of rare frequency. Two is the author had been breast fed reading difficult books, or very rare ways of expression.
Why an author can become addict to write in a gibberish way? Not sure. He can have his brain full of it or… he wants to give a sense of superiority and deepness. If you do not understand some sentences, or most of them, you can have a sense that you are before some piece of wisdom or very advanced knowledge. As a rule, we all are born a black slate, in regard to language. We start to learn the mother tongue and later we bump over the school, where we get acquainted for some sort of a foreign language. As the school goes so much faster than average and even bright children can learn, you would have a feeling during all your school days that you are either stupid or ignorant. If you do not like the feeling of being stupid, do not read deep authors or books.
As you have not a tape to measure how deep is the language of a book, you must use a subjective method you must sample how difficult you feel with a book. If you feel uncomfortable, you must let it aside. You must feel the reading exciting in spite of containing some weird or unknown words.