Yes. The conflicts between Sanji and Luffy in the manga often stem from complex circumstances and character developments that drive the narrative forward.
As of now, Sanji is very much alive in the One Piece manga. The story keeps unfolding with him as a vital part of the plot. The author hasn't written his death yet.
Well, 'leave the pieces novel' might refer to a concept in writing or reading novels. Maybe it implies that the author intentionally leaves some parts of the story, like pieces of a puzzle, for the reader to figure out on their own. It could add an element of mystery or make the reader more engaged in the interpretation of the text.