The seven elements of appeal (pacing, characterization, story line, language, setting, detail, and tone) don't exist in a vacuum, although I'm going to try to get familiar with them one at a time. Detail, story line, and language especially affect pacing, I would think. RA is a neutral practice of suggesting a book, so we want to avoid words with negative connotations like "slow-paced."
I just started listening to The Sacred Book of the Werewolf by Victor Pelevin on audio. It's fiction, translated from Russian. Its plot has the guise of urban fantasy (supernatural foxes and werewolves), but not the pace. A. Huli, the main character, slowly reveals herself to be a fox, alive for thousands of years, with the ability to create illusory realities for people (characterization). She gives in-depth explanations (details) about her kind, and there is little dialog in the book (story line). Chapter divisions are also totally absent in the audio version (story line). All these things contribute to its leisurely pace.
For a medium-paced example, I think Mary Roach's Bonk: The Curious Coupling of Science and Sex is a good example from my recent reading. For a nonfiction science book, it's a fast read, but it is still slowed as Roach meanders through relaying her research experiences. There is no time line, and the book is footnoted (story line), which slow the pace. However, the footnotes are just as hilarious (language) as the rest of the book, bringing us up to a medium pace, along with Roach's encouraging tone; she even writes "stay with me here," at times when the science gets heavier. She also narrates her experiences learning the science, making her the author and a character (characterization), which makes the science stuff easier to relate to and faster to intake.
Red by Jordan Summers is my fast-paced example (and more urban fantasy/paranormal romance than Sacred Book of the Werewolf). It's got werewolves, too, and when the opening scene (prefaced by no background info) is a werewolf lustily devouring a human, you likely have a fast-paced book on your hands. There are multiple mysteries in the book that clearly point toward a resolution (story line) and encourage page-turning. It's told from alternating perspectives of Red and the hero, Morgan, (story line) in serviceable language, only occasionally bogged down by details like the futuristic names of everyday items (e.g., "synth paper," "compunit").