The reason minecraft works is because it breaks the world down into meter-sized cubes. There may be graphical details, but everything is defined on that scale.
Outerra is fundamentally incompatible; it is based instead on a heightmap (though there are obviously some modifications to that, I'm not sure what). The difference between a height map and a minecraft like "voxel" space is very large- and making a switch would critically change how the world is structured.
The closest we could see is something where you can place buildings (or building parts such as walls and doorways and floors) on a grid, and possibly even dig trenches into the ground or even make tunnels and caves below the terrain surface- but it won't be the same as what Minecraft can do.
Outerra has the potential to be very unique- much like minecraft itself is. As tempting as it may be to mash two great things together, it is better to allow Anteworld/Outerra to be its own thing.
