We've just updated our Roadmap for The Long Dark Sandbox to version 1.2, which includes an aspirational feature/content list for our next Sandbox Update.
Check it out: http://hinterlandgames.com/the-long-dark/roadmap/
Please remember that this is an aspirational list, meant to give you an idea of some of the things we are working on, and some of the things we hope to work on. It's possible that some of the things on the list may not end up in the game.
Also, please note that over 2/3 of the development team is working exclusively on Story Mode content and features, which has an impact on Sandbox update scope and frequency.
Thank you for your understanding!
- The Hinterland Team