I've read the manga, which by the way is quite faithful, the novel is about the classic transmigration into a game world, with MC being snubbed as a curator. Then it turns out that he is a madonna tactician capable of revolutionizing the way monster hunts are tackled and parties are managed.
He doesn't invent anything new but it sure doesn't make sense to give a 2.5 .. even if there's definitely better, I don't understand why most users aren't rate enabled.
I'd give it a 4 if that's your thing. I would recommend you to read the manga first because the initial phase of the novel is quite slow.