Oh you guys with your derailing.
Anyhow, Kompressor said multiple times that they are not coming back.
But don't worry, brick terrain doesn't look too bad.
And aside of that, there are a couple of Terrain bricks too!
You should try them out, this way you can build your own terrain easily. ;)
Terrain and interiors just were outdated features, which would slow down any development a huge amount.
So that is why they decided to kill them. :)
They are not coming back and you will see that it will be all worth it.
Instead of loading maps with terrain and interiors, you probably will have to load a save or start some kind of terrain generator even!
Also, i don't know if you are aware of this, but there is a nice video of what is coming:
Video
Poll