Regardless, it's pretty obvious that they didn't (or at least no longer, it's possible Sierra Lee had one as the original writer) have a real outline or structure for the story besides the start and endings.
Been following her solo project
The Last Sovereign for years now and there's no way that project would still be keeping itself consistent (down to the smallest detail, as best I can tell) without an extensive plan going back to the beginning. I'm pretty sure this is all on the other guys.
In one sense, this vindicates everyone who said Sierra Lee was more than just a writer and the project would fall to pieces without her. But in another sense, the remaining team is estimated by Graphtreon to still be making somewhere between 1k and 4k USD per month, which is a pretty good side hustle/scam for people who only crap out one "significant" content update per year. So in a purely financial sense, that vindicates people who said Sierra Lee wasn't needed - they can probably keep milking this a long time, especially if they live somewhere that's a lot of money.
A cynical person might say Nomo and pals just used Sierra Lee long enough to get a strong start, because if you get a strong start you can get a critical mass of people who get drawn in without noticing the rate of progress, and rarely bother canceling their pledges. It's a tragedy for anyone who wanted to see another quality story from Sierra Lee, since the original ideas she had may never be realized, but hey, titties. Or something.