I'll admit some puzzlement over the game myself; in my opinion, I think the game's a little overblown; Terraria, IMO, is a better sandbox. However, what appears to be the case is that it allows for full 3D artwork, but ALSO has a unique-enough gimmick (being based on un-filtered cubes) that it actually feels NOVEL to create things in it, versus more commonly-accepted artistic methods available, such as, for instance, in Second Life or heck, any true 3D modeling program.
Perhaps my bias against Minecraft is that I almost had expected it to be more of an "solo Dwarf Fortress in 3D," and it was far, far less ambitious than that.
[citation][nom]killbits[/nom]Morrowind[/citation]
Just as a correction, Morrowind placed a VERY heavy emphasis on graphics. The reason it doesn't look impressive now is, well, because it was old. It'd be like claiming that Quake focused on "gameplay over graphics." (or better yet, Unreal 2: The Awakening) In time even Crysis will look dated. (it actually kinda does, at least compared to once you throw in the "ultra-realism" mods)