The writing style might be the culprit. If it was overly complicated or too simplistic. Complicated writing can make it hard to follow the story, while simplistic writing can seem childish. Another factor could be the themes. If they were too dark or not explored in an engaging way.
The characters could be a big turn - off. If they constantly made stupid decisions or were just mean for no reason. It would be really hard to like the novel then.
Well, spoilers in light novels related to gamers can be really annoying. For example, if you're into a game - based light novel series and someone reveals a major plot twist about a character's in - game power - up or a crucial event in the game world that the characters are part of. It can ruin the excitement of discovery when you finally get to that part of the novel.
Well, there are some major plot turns in 'A Will Eternal' that you wouldn't expect. However, I suggest you discover them yourself while reading to fully enjoy the story.
Another option is to keep it to yourself for a while and reread it. Sometimes, when you know the spoilers, you can pick up on little details that you might have missed the first time. And as you do this, you can think about whether there are any deeper meanings or messages in the story that you didn't notice before.
Maybe in that fanfiction, Naruto's over - eagerness to be recognized could be misconstrued. His loud and boisterous nature might annoy people. For example, if he constantly interrupted others or pushed his ideas too hard without considering others' feelings, it could lead to dislike.