This anon sums it up perfectly for me. DN provides trace amounts of food-for-thought (but not too much, that'd be too hard on our audience of little kiddies) wrapped in a neat bundle of mediocre suspense/supernatural genre.
Faggots that play it up as being significant for the values it challenges (LOL MAYBE IT REALLY ARE RIGHT TO KILL BAD PEOPPL, HOLY SHI) only do so because in DN it's handed to you on a fucking plate, and any 9 year old can pick up on it and feel clever for doing so. Protip: it's not in anyway groundbreaking in what it does, and not particularly intelligent in how it does it.
TL;DR - DN overrated and not, in fact, any good.