I think part of the reason there are so many plot threads - beyond so many authors - is the very nature of the serialized story. It's like a TV show, where every episode needs to be exciting in itself. Add to that the fact that everyone is trying to make their post the most interesting and gripping, and it lends itself to moving through plot rather quickly.
I also think that's why we don't see as many "nice" characters anymore. The stereotype in the ROC seems to be that nice characters are boring and predictable (no doubt due in part to Redwall canon), and I think most people steer away from that in favor of trying to make flawed, realistic characters. Granted, it's possible to have both, but when your survival in the story depends on a character that is more interesting than at least one other, it's easy to shy away from that "woodlander" mentality.
As for this story, in particular, we had a great cast of writers and characters, but often had a difficult time coming to plot consensus throughout, and it definitely showed.
All that said, thanks a million times over for sticking through this entire thing, Vizon. An interested audience makes all the difference in the world, and I can say without exaggeration that you made the story not feel like an exercise in futility.
Your comments about the story's dark nature are well taken. A lot of that, I would say, has to do with the setting. It's more modern than most, which raised a lot of questions maybe not asked in others. Due to a more politicized and connected world, events had wider reaching consequences. There weren't isolated incidents that happened in one place; rather, they affected everyone. It made it harder to know where to stop the story. Sure, we could have ended it after making it to the surface, but - to me at least - that didn't feel complete. If this had been a story a hundred years before, it would have made sense that this could have all been caused by a lone bunch of crazies, and it was all over once we surfaced, but that felt like selling ourselves short. As Orson Welles said, “If you want a happy ending, that depends, of course, on where you stop your story.”
That said, I like to think of Luummae's most recent post as the end of the story proper, with the villains finally defeated - or at least justice on the way. And then my last post is the first of the epilogues proper, showing the aftermath of everything. There's a trial going on, sure, but it's also showing how Mila - and, to a lesser extent, Sal and Luu - has coped with events nearly a year later. And finally, we'll get a closer look at how Luu and Sal have coped, but also be shown where they go from here.
Now that I look at it, though, I think you're right that my epilogue could also work as the ending of the story. And it's all in the same board, anyway, so both views are totally cool.
On a final note, this is rather turning out to be a Lord of the Rings never-ending endings scenario, isn't it.