pistachio (the dev) wrote something about this some time ago:2. When it comes to the next update. Try to plan it so it'll release in 6 to 9 months and if it looks like it might take longer. Break it up into smaller parts, so there's always something being released in a reasonable amount of time.
[pistachio]
I think I started this update with a wrong mindset as well. We had two quests in mind that we really liked and we went for then, without considering their complexity (I thought having fewer quests, i.e. 2 instead of our usual side-story's 3 would be sufficient in speeding things up)
In the future, if a story we really want to tell takes this long, we will break it up into multiple releases (that's what we will do, probably, with the next part of the main story)