Snapshot 14w17a has brought something absolutely amazing to the table of Minecraft. It actually makes me really want to play it again.
There is a new customizable world generation feature when creating a new world. You can change just about anything - the sea level, whether grass will spawn, the sort of structures that can be generated, (i.e. villages, strongholds etc.) the abundance of dungeons in the world, the spawn height and vein size of ores, (you could make diamonds spawn up to the top of the map in veins of 80!) the size of biomes, (or make the whole world one biome if you want!) the amount of caves, the scaling of the world, YOU CAN MAKE THE OCEANS FUCKIN' LAVA AND PUT GRAVEL GODDAMN EVERYWHERE and lots of other weird but fantastic technical world generation shit.
But wait... there's even more.
There are also presets that can be used if you get lazy or like them. These are:
-water world: basically, the sea level is REALLY high (above the clouds!) and there isn't much but ocean. Not particularly great, but would be useful in making survival island maps etc.
-isle land: floating islands. It's some avatar shit, man. The world will generate pretty normally but there will be floating islands, some big and some small, which looks very, very cool. However, the biggest problem with this is that you will get lots of random one block pieces around and little 2x2, 3x3 etc. cubes of dirt floating in the air and shit, which is kinda annoying. Nonetheless, cascading sky waterfalls and floating islands - brilliant.
-caver's delight: a world with lots and lots and lots of caves. But it's not like the normal world as such, as it is almost like there is a platform upon platform sort of structure, the underground looking a little distorted and all, but very, very cool. Exposes dungeons, abandoned mineshafts, etc. which is also a nice feature.
-mountain madness: you guessed it, mountains are bloody HUGE, pillaring sometimes all the way to the top of the map. It makes very cool sort of mountainous and bridged world generation, but there are lots of chunks of solid rectangular prism shaped pillars going up high, which look sort of like cool spires, but all very glitchy and out of place, which is a shame. (but they're sure to be fixed eventually!) However, it is NOT the same as amplified mode.
-drought: everything is dry and desert-y and I think there is no grass. [citation needed] I didn't really play around with this one but could make a cool wastelands survival. (and is a cool feature nonetheless)
-caves of chaos: with out a goddamn doubt my favourite. This is much like caver's delight, except the world is even more layered (shrek likes that) and distorted and weird, and the sea level is at 6 (which means it is literally one layer above bedrock, meaning bedrock is exposed at the bottom of the map and stuff) and is generally AWESOME. Lavafalls, huge mountains, distorted cave worlds - it makes you feel like you're in a weird altered dimension of Minecraftia. Like caver's delight it also exposes mineshafts (and probably also strongholds, making that aspect really awesome too!) and other generated structures, and in one world I used, I even found a village on a floating island which floated above bedrock. Very, very, VERY cool.
-good luck: A world where everything is hard. Oceans are lava, there is no grass, animals are sparce, gravel is fucking everywhere; you will need some good luck to survive here. (make the biome desert to have a mega challenge! That would be basically impossible!)
Once again, you don't even have to use any of there features. You can just create a new world as normal, and there are still options of superflat, amplified etc. You could only change the spawn height of diamonds perhaps, and just create a world with lots of diamonds in it! Or if you like taiga, you could set the world to a taiga world, so that everywhere you look is your favourite biome. There are limitless opportunities for these worlds!
However, keep in mind that this is still a snapshot and bugs/world errors are often likely to occur. There were some pretty bad world generation bugs in 1.7, and they appear to be a little less common now, but in all world generations you do often get solid chunk errors. But it's not in a big long line like in 1.7, they're just here and there.
But don't let that turn you off it. Minecraft is now in 14w18b and the full update it set to come out this very month.
Here's a little screenshot I took on a caverns of chaos world. Sorry the render distance is pretty low, I had to turn it down because of the lagginess.
By the way, I'm at about Y=180 there, just to give you an idea of how high the map generates. There is plenty of land above me.
So go ahead and check it out here: http://minecraft.gamepedia.com/14w17a and also on Minecraft itself. Experiment around and use the presets, it's very cool.
Swaggy out.
There is a new customizable world generation feature when creating a new world. You can change just about anything - the sea level, whether grass will spawn, the sort of structures that can be generated, (i.e. villages, strongholds etc.) the abundance of dungeons in the world, the spawn height and vein size of ores, (you could make diamonds spawn up to the top of the map in veins of 80!) the size of biomes, (or make the whole world one biome if you want!) the amount of caves, the scaling of the world, YOU CAN MAKE THE OCEANS FUCKIN' LAVA AND PUT GRAVEL GODDAMN EVERYWHERE and lots of other weird but fantastic technical world generation shit.
But wait... there's even more.
There are also presets that can be used if you get lazy or like them. These are:
-water world: basically, the sea level is REALLY high (above the clouds!) and there isn't much but ocean. Not particularly great, but would be useful in making survival island maps etc.
-isle land: floating islands. It's some avatar shit, man. The world will generate pretty normally but there will be floating islands, some big and some small, which looks very, very cool. However, the biggest problem with this is that you will get lots of random one block pieces around and little 2x2, 3x3 etc. cubes of dirt floating in the air and shit, which is kinda annoying. Nonetheless, cascading sky waterfalls and floating islands - brilliant.
-caver's delight: a world with lots and lots and lots of caves. But it's not like the normal world as such, as it is almost like there is a platform upon platform sort of structure, the underground looking a little distorted and all, but very, very cool. Exposes dungeons, abandoned mineshafts, etc. which is also a nice feature.
-mountain madness: you guessed it, mountains are bloody HUGE, pillaring sometimes all the way to the top of the map. It makes very cool sort of mountainous and bridged world generation, but there are lots of chunks of solid rectangular prism shaped pillars going up high, which look sort of like cool spires, but all very glitchy and out of place, which is a shame. (but they're sure to be fixed eventually!) However, it is NOT the same as amplified mode.
-drought: everything is dry and desert-y and I think there is no grass. [citation needed] I didn't really play around with this one but could make a cool wastelands survival. (and is a cool feature nonetheless)
-caves of chaos: with out a goddamn doubt my favourite. This is much like caver's delight, except the world is even more layered (shrek likes that) and distorted and weird, and the sea level is at 6 (which means it is literally one layer above bedrock, meaning bedrock is exposed at the bottom of the map and stuff) and is generally AWESOME. Lavafalls, huge mountains, distorted cave worlds - it makes you feel like you're in a weird altered dimension of Minecraftia. Like caver's delight it also exposes mineshafts (and probably also strongholds, making that aspect really awesome too!) and other generated structures, and in one world I used, I even found a village on a floating island which floated above bedrock. Very, very, VERY cool.
-good luck: A world where everything is hard. Oceans are lava, there is no grass, animals are sparce, gravel is fucking everywhere; you will need some good luck to survive here. (make the biome desert to have a mega challenge! That would be basically impossible!)
Once again, you don't even have to use any of there features. You can just create a new world as normal, and there are still options of superflat, amplified etc. You could only change the spawn height of diamonds perhaps, and just create a world with lots of diamonds in it! Or if you like taiga, you could set the world to a taiga world, so that everywhere you look is your favourite biome. There are limitless opportunities for these worlds!
However, keep in mind that this is still a snapshot and bugs/world errors are often likely to occur. There were some pretty bad world generation bugs in 1.7, and they appear to be a little less common now, but in all world generations you do often get solid chunk errors. But it's not in a big long line like in 1.7, they're just here and there.
But don't let that turn you off it. Minecraft is now in 14w18b and the full update it set to come out this very month.
Here's a little screenshot I took on a caverns of chaos world. Sorry the render distance is pretty low, I had to turn it down because of the lagginess.
By the way, I'm at about Y=180 there, just to give you an idea of how high the map generates. There is plenty of land above me.
So go ahead and check it out here: http://minecraft.gamepedia.com/14w17a and also on Minecraft itself. Experiment around and use the presets, it's very cool.
Swaggy out.