I love the hell out of FSN. I really do, I have played it to completion twice, have seen all the anime adaptations save Heaven's Feel, and am a GIANT fan of Type-Moon in general. That being said, the novel, like many Japanese VN's is over written. It never says in one line something it could instead say in ten.
Maybe it's the translation, but FSN has around 924,000 ~ 1,000,000 words in it. That's about as many as the first three books of George R. R. Martin's a song of Ice and Fire. It's minimum 350,000 more words than "War and Peace", it's 500,000 more words than "The Lord of the Rings". It's fucking long. Too fucking long. It needs an editor, badly. I can still love it and understand that fact.
It's not alone. Stein's Gate, another really good VN has 620,000 words. It also feels over written. One I hear recommended a lot is Grisala, but apparently that's AT LEAST as long as FSN, and that's about 50 hours of pure reading.
Western VNs tend to have the opposite problem, in that many are too short, but especially with the life sim ones, they give no fucks about the players time.