How does the terrain generator work? Are you laying down layers of materials? If so, you'll be missing some cool landscape features such as overhangs.
I actually made something similar over a year ago. The way I did it was to use 2D Perlin noise added to a vertical gradient; the values of the noise above a certain threshold were stone, and those below were air. Values in the middle would map to soil, so you get a nice band of soil between your air and rock. Once you have a basic terrain shape, you can decorate it by adding ores to random stone tiles, and grass to soil with air above.
It's suppose to look minecrafty. It's not gotten far at the moment. I'm still learning but I'll try see if I can get overhangs in.