Is there a legal precedent on how copyright can be used against game clones?
I know that there is for board games, and there it says that the art and the rulebook cannot be identical, but that game rules aren't protectable. So it's basically the same level of protection that e.g. a painting would have.
If the same thing holds true for video games, then "The gameplay being similar" shouldn't matter at all, and the only question is whether the art is too similar.
Considering that the art for voxel games is limited by technicalities (1m size blocks are required by the gameplay) and the low-resolution texture art style, I would naively guess that there's not much room for differentiation and thus unless the textures are actual 1:1 copies of minecraft textures, there's not much that can be done there either.
There aren't a lot of ways you can draw a low-resolution square birch texture.