The Minecraft [Official Site] developers have announced The Exploration Update and they have already released a development release for it.
They have finally gone back to adding in some worthwhile content to make worlds more interesting to explore.
They have added in "Illagers", who are the villager’s outcast cousins and they will reside at the Woodland Mansion. They aren't very welcoming apparently, so bring your sword.
- Added cursed enchantments
- Added the Observer block
- Added escape portals in The End
- Added the Shulker Shell and Shulker Box
- Added exploration maps
- Added the Woodland Mansion
- Added Illagers, and the Vex
- Added Llamas
- New command: /locate
- Bug fixes
There's more to it, so read their blog post here. That doesn't cover all of it of course, as they want you to discover some for yourselves.