Minecraft wiki entry for Development_versions, associated text: Readded Amplified and Large Biomes, they have been adapted to the new terrain.
Amplified had terrain with following characteristics:
Rounded terrain at Y=320, instead of Y=256 previously.
Doubled offset above sea level.
Greatly increased 3D noise values, resulting in lower factor values inversely.
Doubled peak jaggedness.
Large Biomes had terrain with following characteristics:
Most biomes are four times larger, except mountain peaks and rivers.
Multinoise is slowed down by factor 4 for temperature, vegetation, continentalness, and erosion, but not for ridge noise.