Well, 'noticed' is another word for'seen'. When it comes to 'novel', 'original' is a great alternative. The word'seen' implies the act of visually perceiving something, and 'noticed' has a similar meaning but might imply a bit more of an awareness. 'Novel' means new and different, and 'original' also gives the sense of being new and not a copy.
There's no easy way to determine if the 'Overdone Devil Exterminator' light novel is popular. Some light novels become popular due to their anime adaptations, but if this one doesn't have that, it may rely solely on word - of - mouth, the quality of the writing, and the appeal of its story. It could be popular within the light novel community, but not well - known outside of it.
I'm not entirely sure which specific 'overdone light novel' you're referring to. There are many light novels out there, and without more context, it's hard to say exactly what it's about. It could be a story that has been overly used or cliched in some way.
I'm sorry, I don't know the exact plot of this light novel as it's not very well - known to me. It might involve a protagonist who is an exterminator of devils, perhaps with some unique powers or skills to combat them.
The key is to be original. Maybe combine genres that aren't often mixed or tell the story from an unusual perspective. And don't be afraid to take risks and challenge conventional storytelling methods.