I don't know what definition of "clone" you use, but in my eyes you are using the word too liberally here. Was there any stage of Minecraft development that was even remotely similar to Dwarf Fortress in concept? When I started playing it it lacked, say, crafting, and the only concept it really shared with Dwarf Fortress was the idea of generating terrain procedurally; a concept shared by many games, and one that makes Minecraft compare to Dwarf Fortress like a propeller beanie compares to a wind turbine.
