Wait... so does it mean Nomo was the one creating the bottleneck in this project?
A: We simply don't know. See below for a more detailed response.
Answered in regards to Sierra (who left years ago) per topic of the quote --- No one outside of the development team knows what happened behind the scenes. All we know for certain is that Nomo and Sierra had worked together before on a previous game (Noxian Nights) and that they worked together for a while on this one (KoD) before Sierra left. There's been much speculation but among the ideas that had been floated were: differing visions on the direction of KoD, conflicting work ethics for this project despite the success of NN (including possible "bottleneck" problems), time constraints by Sierra while she worked on her own solo projects, and how the revenue should be split between them. We simply don't know why Sierra left the team; all we know is that the relationship between the two ended "amicably".
Answered in regards to the current Hreinn Games team --- The current team consists of Nomo, Ndsferrari, and Monsinne. They've been together for a long time; thus, any issues or concerns should be directed with this current team in mind. This team, quite frankly, is gawd-awful at communicating with their fanbase. In regards to the team's current format, no one knows for certain what each team member actually do, what their responsibilities are, or what each of them have contributed to KoD. It's assumed that Nomo does the majority of the art if not all of it, and that Nds and Monsinne are the coders and writers for the project (with creative input from Nomo). Some believe that Monsinne is the current lead writer for the game's story. Again, no one knows what's holding up the show -- the "bottleneck" -- or what each of them are supposed to be tackling because they're simply not transparent on the matter. Boy, on the otherhand, they're excellent at coming up with excuses while leading people on with what little news of subsistence they that occasionally toss out. This is a stark contrast, imo, to how the early duo communicated with their fans which also included multiple outlets.
(Take Sierra, for instance, she communicates with her fanbase on the regular along with frequent news updates for her projects including unexpected issues encountered.) As such, many believe Hreinn Games' credibility is shot to hell when it comes to the truthfulness of what little news that they share. This is something that they need and must work on going forward if they don't wish to further alienate their fanbase.
So why does it seem like there's a "bottleneck" that's slowing down the development of this game? We just don't know. We don't even know if there even is any kind of bottleneck. Maybe the current team is just slow, but people are free to make educated guesses.