I'm a librarian who loves anime, manga, and reading a wide variety of genres.
OMG, I'm finished. I loved the first season of the anime, despite its pacing issues. Unfortunately, it turns out that whoever adapted the anime actually made quite a few improvements, because the original book's pacing was excruciating. Also, I can't believe I'm saying this, but the anime actually had less fanservice than the book.
In the afterword:
"This book is an edited and revised version of an online serial I started writing in April 2010. When the story was turned into a book, I changed the setting a bit and revised the text to improve the quality of the writing and its readability."
Uh, not enough, but I suspect that truly fixing the story would have involved scrapping at least the first couple books' worth of material and complete rewriting everything.