@Christopher : Your point being, many genres have very narrow openings to the story, look at how many westerns open with a gunslinger wandering into town, would you call "Last Man Standing" unoriginal because it opens with an gun for hire wandering into town? No, though it is a remake of one oh Kurosawa's films. they differentiate themselves is on how the story progresses from that point. The longer the story is intended to be (and given the author writes novels long is likely) the more time you need to give it to differentiate itself.
Remember novels build slower then series made manga as the first source, i have read plenty of novels where the first few chapters are more introducing characters then anything else, and the story comes after they cast is established. No one would expect those novels to be super unique from the first half of the prologue, and this is likely only as far into the story as that.
@xyzzy : you do realize most writers stick to the genre they get success with, and do not venture from it much. Even the big names are mostly 1-2 genres, but many specialize. You get a reader base and it is safer to keep with stuff that the readers like, actually unless you are famous enough to sell a book on your name alone, switching genres is a huge risk as you can jot be guaranteed to carry over your established fan base.