Minecraft will be getting a huge terrain generator overhaul in version 1.8. Under your world type selection there will be a new Customized option and in the settings for this world type you’ll find 16 sliders which can be used to affect various aspects of Minecraft’s terrain generator, but you can also type in values directly. You also have complete control over things like the sea level and what structures you want to generate. Pretty sweet, eh? Check out this video by the Mojang team showcasing some of the presets and sliders you’ll have.