I feel MM got disappointed in voxels, they bring all that trouble with bad graphics and performance and I'm afraid his next game would be no voxels. Which saddens me. To combat all those top selling games you really need to be special PLUS have a miracle luck to hit that elusive string that no one can put a finger on. Lets hope you will succeed, but my point is:
From a business point of view, making a plain sequel, 7d2d-2, with voxels again, but on a new level, with all the accumulated knowledge and the dream team you are having now, would be a guaranteed success. And it will not take all those years again to make it.
But that is a view from my sofa..