I'm up for finding some new book-bloggy friends, so I thought I'd join in on the Literary Blog Hop. I like the question they've posed this time around, because it is something I actually have opinions about!
First off, "difficult" is relative. Simple things such as pace, topic, and setting can make a big difference in how difficult it can be to get through a book. I've read small, simply written books that have been very difficult to get through due to the topic (ahem, Alchemist, hrm) and small, well written books that are made painfully difficult just because the setting is one I dislike (uh, Melville, I'm talking to you). As far as the writing structure itself, (vocabulary, symbolism, sentence structure, etc.) so much relies on the reader's preferences and maturity that a concrete definition isn't possible.
All that being said, I'd like to talk about my preferences as far as the difficulty in writing structure and style. I've definitely grown as a reader, (see my recent Gatsby post for a great example,) and books that I didn't appreciate when I was younger I am able to appreciate now. Not only that, but tastes change and develop. One thing that really gets my goat, though, is when a work seems to be difficult just for difficulty's sake. I'm not a fan. In fact, I think it often comes off as arrogance. I don't read in order to decode a puzzle of super-embedded subtle symbolism--it just isn't an interest of mine. On the contrary, I'm impressed when an author can use seemingly simple language to create depth, layers, and complexity. When a book can be fairly simple to read and yet spur deep thought, spin complex themes, and ignite my passion and imagination, I'm enthralled. There are many beautiful books that exhibit this characteristic, and I've found that they usually share the characteristic of being enjoyable on many different levels, for different reasons, and at different times of life.
The term "Literary Fiction" does imply some level of difficulty, though. Even titles that are easy enough to read still demand an interest in personal growth and the development of your mind. So there: the answer is yes and no. :)