From Official Factorio Wiki
This is a list of planned additions and changes for Factorio's next major release 0.16.
- Artillery train
- GUI/UX improvements
- Mod portal improvement (rewrite)
- Map generation improvement (related to the updated high res terrains and decoratives)
- Train pathfinding and collision checking optimisations
- Additional smoke related optimisations
- Lamp related optimisations
- Item stack optimisation
- Optimisation of electric network update logic
- Optimisation of logistic robot movement
- Group multiple item icons to one sprite in order to optimize rendering of saturated belts
- Find a way to show connected walls + pipes in a blueprint
- Confirm blueprint deletion
- Fluid squashing in pipes
- Map interaction improvements
Semi-bugs or small things
- A train will no longer block its own path with chain signals
- Make programmable speaker 'Global playback' only apply for people on that force
- Make electric network UI less weird with lots of accumulators.
- In the future, construction robots will stop following their repair target when the target leaves the construction zone. 
- Construction robots now immediately know when their target has been repaired (by hand etc), instead of realizing it when they arrive at the target.