Here is very first variant of proposal that was changed to entity creator because of lack of mentor resources at that moment.
1. Add new simple tasks with proper gui that represent core things that player can do: open/close box, get/put items to the container, put one thing on another, push/pull, etc. This step will require to consider what tasks could could be done without physics engine and to think what more tasks will be useful.
2. Add more “construction” tasks: shape tree log, connect them together (with nails or just simply put one on another)... Here, if not available in Atlas, format of efficient storing and transmission (if house contains 12000 nails, than we probably shouldn't send them all to client) of composed objects with connection to finite number of existing 3D-models should be invented. At first, existing proposals like “Tiling models” in WF, and mechanisms of OGRE should be worked on.
3. Improve interaction with NPCs. Currently, in WorldForge, NPCs are very user-unfriendly. At least, in client some shop-interface should be done and on server their logic should be improved.