Optimizing voxel data read times is a small part of the puzzle.
The primary challenge of voxel engines is adapting the rendering engine to accommodate for dynamic modifications. Light maps, shadow maps, bump maps, occlusion maps, texturing, LOD geometry... whatever. All kinds of things that are traditionally statically generated, need to be regenerated on the fly or done without. Which is why minecraft went for the retro-aesthetic, there wasn't really a choice in the matter back then. We're only now starting to see full-fledged voxel engines that can support a non-retro look, but they are still a long way behind the aesthetics that can be achieved with a normal engine.
> Which is why minecraft went for the retro-aesthetic
I though main reason why MC is retro is that Notch is not really an artist - he just wanted to create graphics quickly. And he brilliantly turned this into an advantage - I can't imagine MC without iconic square pigs and pixelated pickaxes.
Well he's not Michelangelo obviously, but low res pixel art is still art. Compare it to some of the clones or infinimer and it's clear that care went into the aesthetic.
The primary challenge of voxel engines is adapting the rendering engine to accommodate for dynamic modifications. Light maps, shadow maps, bump maps, occlusion maps, texturing, LOD geometry... whatever. All kinds of things that are traditionally statically generated, need to be regenerated on the fly or done without. Which is why minecraft went for the retro-aesthetic, there wasn't really a choice in the matter back then. We're only now starting to see full-fledged voxel engines that can support a non-retro look, but they are still a long way behind the aesthetics that can be achieved with a normal engine.