When you lean too heavily on story at the expense of gameplay, you're just reading. Sure, story matters, but for me, a mediocre story can be forgiven if the gameplay is good. I've played lots of "regular" games where the gameplay is great but doesn't rely heavily on story and they've been a lot of fun. The thing for me with VNs is that without gameplay, the story HAS to be good. So to answer the question, I probably wouldn't call a game that ONLY has good writing to even be a game anymore, but stories can have their place. I've passed a few hours on Dumb Koala and there's no gameplay at all with them.