At first glance, my reaction was, "sounds like a bookstore." The fiction in our kids' section is mostly arranged by reading/listening level; the only exception that I would call strictly fiction is the Fairy Tales/Folk Tales/Mythology section. In particular, our kids' nonfiction section (smaller than that of most libraries, but certainly an active section) is categorized similarly to what the article describes. In fact, we recently rearranged it
Metis, the system described in the article, sounds wonderful for browsing--for finding the kind of book you want and then stumbling upon the perfect book plus two or three related ones. I wonder, though, if it's disconcerting for patrons who already have a specific book in mind. In fiction, particularly, readers are used to knowing exactly where to go once they know the author's name. But is Spaceheadz humor or sci-fi? Is Inside Out and Back Again historical fiction or poetry? Maybe, though, there's fun in those questions, or in finding new ways to describe your favorite book. I'll admit that I find that aspect of shelving satisfying.
There's also the question of whether the Dewey Decimal System is an important skill for school libraries to teach students so they can use libraries later in life. My tentative answer: maybe students don't need to learn Dewey specifically; what they do need to learn is how to search, how to figure out and navigate a system. (Lots of libraries use the Library of Congress system, anyway.) Maybe learning to search means figuring out the categories on their own. Maybe, and more likely in this day and age, it means using some form of online catalog based on whatever system is in use.
I don't think there are perfect answers (can we put that Jackie Robinson biography in two places)? But I'm very glad that, instead of adhering to a system out of habit, librarians are asking the questions.