I agree with everything else you've said, but I've always felt that the above is one of the worst pieces of literary advice ever handed out. It's not quite as bas as 'write what you know', but then in my view neither is genocide. I gave lectures on the creative writing process for a while, and one of the first things I tried to convey to people what not to obey the above rule, which they have all had drilled into their heads by Stephen King's 'On Writing'. I am not generally in favour of banning books, but for that one I might make an exception.
If everything in a story (of any form, be it novel, film, game or other) is devoted to advancing the narrative then what you end up with is a bloated plot that is unlikely to convince a reader/viewer/listener to care about it. Plot is ultimately derivative, and whether you believe Gozzi that there are thirty-six, Tobias that there are twenty or Aristotle that there are only three, it is commonly accepted that narrative is finite, and since it is finite it is ultimately derivative, and because it is ultimately derivative it is seldom engaging.
I struggle to put my finger upon a single text that I enjoy for the story alone. Outside of modernist work narrative is the critical trunk around which most fiction is built, but a trunk that is not adorned with branches and leaves is pretty fucking boring to look at. This is not to say that plot cannot be entertaining, but a plot can ultimately only be as entertaining as the environment in which is transpires. This is why 'Who's Afraid of Virginia Wolfe' and 'Twelve Angry Men' are works of deep and moving artistic genius, but me simply recounting the plots of those plays is something that nobody cound possibly be persuaded to care about.
What engages a reader is precisely those elements of a text that do not advance the narrative. Characterization, description, imagery, summarization and exposition ( maybe not so much). Do you have any idea how long Midnight's Children would be if you cut out every paragraph that could justifiably be considered to be purple? You'd be axing a majority of the book, and turning one of the seminal works on magic realism into an extremely average story about post partition India.
Yann Martel's Life of Pie doesn't bother trying to advance the narrative at all until one third of the way into the book. The opening chapters are almost all anecdotes about the practice of zoo keeping. This is the same for a great deal of quality fiction, which to a greater or lesser extent prioritises world building and character development ahead of pushing forward the plot. If the reader has not been drawn to care about the characters and their world then the plot is not going to hold their attention. It's why nobody reads those incredibly dense spy novels despite them having narratives that make the Booker Prize short list look simplistic.
And then of course there is the fact that writing for its own sake is an essential part of any text. The era of realist fiction ended a few hundred years ago. We've had Virginia Wolfe and her fellows teach us about modernism, and we've transcended quite some distance from that in the past forty years. It is now widely recognised that an extract from a text can exist entirely for its own sake. Ian McEwen can spend six pages talking about strangers by the side of the road, and the reader will lap up every irrelevance detail for no other reason than because it's masterfully written. Hell, a lot of modernist material issues a gigantic 'fuck you' to the concept of advancing a narrative at all, and whilst it's not to my taste one cannot reject its success as a means of expression.
Obviously things become somewhat more complicated when dealing with film and television where a far more stringent time constraint is imposed and the writer's hand is forced to contain a set amount of narrative in a set timespan. There's also the fact that, since one is dealing with a visual medium, almost everything can justifiably be presented as narrative in it's own way. Even there however it is recognised that not everything need advance the plot. Find me a film that doesn't contain at least half a dozen scenes that could be shaved without a single person in the audience noticing and I'll consider you to have done very well for yourself.
The beauty of unlimited mediums such as novels, or in this case video games, is that they don't have and kind of real time constraint placed upon them. The creator has almost total freedom to present the characters, world and story however they feel best, and as such there is absolutely no need for every word to be advancing the narrative. Hell, I'd even go so far as to say with a video game (which usually live or die based on immersion, which is closely tied to world building) advancing the narrative is even less important. There's a good reason for the hundreds of utterly pointless NPC's who litter each and every JRPG ever produced.
So yeah... those ten worlds you typed... they're wrong.
