I am sure this has come up already but if you allowed characters to be exported from Fallen London and imported into Sunless sea you would probably end up pushing more sales of Sunless sea and most assuredly increase account creation and potential sales in Fallen london. Starting off Sunless Sea’s as a seasoned inhabitant of Fallen london would add some excellent story elements. If this creates and unbalancing then perhaps script a new story line that allows players to become a ship captain and a acquire a ship, this could open up a plethora of story lines. This does not have to be easy. This seems like it would be a win win enterprise that could potentially be quite easy to implement.
I think there are plans for those with Zubmarines in Fallen London to unlock Zubmarine content in SS, but they’re a long way off. There’s a lot of content on the Unterzee already (in FL), but more would absolutely be taken in happily =)
They actually thought about that, and I assume what is described in the following post will get implemented at some point: http://www.failbettergames.com/importing-fl-characters/