It's finished when it's finished. And yes I work on FS, but not on the Quest Content of the DLC atm.
Edit:
To expand on my and Bloodpain's reply: I do tons of stuff for the maingame, basically all the maingame fixes come from me with a few exceptions, like localization fixes and stuff that I have no idea about or bug fixes of external people.
The reasons for the ongoing patch support are:
1) Bugs need to be fixed in order to make Forgotten Stories work properly, i.e. the Crafting system needed to be fixed and reorganized/restructured (The major rebalance / readjustment and the adding of the "Phasmalist" - a class that relies on crafting/enchanting - will happen with Forgotten Stories). I could have fixed stuff only for FS, sure - but that wouldn't be fair towards the players, if we keep all the fixes in the Developer build. When we are able to fix something, then we should do it and patch it.
2) If noone is going to fix bugs of the maingame, we would just add more bugs with FS on top. And that wouldn't be pleasant to play - no matter how good the story/stories are written.