I'd rather add a 9 on the scale for extreme outliers. There may be a total of five stories in all of CYStia that'd merit a '9' length, and at the moment the 4/5/6/7/8 thresholds are fairly meaningful in getting an impression of how long the story experience will be, and account for an overwhelming majority of content on the site.
That said, no one would make this kind of a wish without a reason, I'm looking forward to your storygame that's been in the oven for the last two months even more now.