People should start with building a voxel engine as performant as possible that would allow for player count to scale with hardware to eventually allow for millions of players on the same map.
What makes games like minecraft great is the gameplay that naturally emerges from player interaction. This aspect of voxel engines should be actively pushed to the absolute limit.
People in the gaming sector tend to apply new tech to improve old overdone gameplay (like making games more hd) instead of enabling previously impossible experiences.