Redstone Update

The Redstone Update is a planned major update labeled as 1.5. It was announced at MineCon 2012 at the Future Updates with the Minecraft PC Team and The Future of Mod API talks. It will probably be released sometime in January or February 2013.

Planned changes
Note: Most of the changes listed here have no detailed references since most of them were mentioned at MineCon, especially the Future Updates with the Minecraft PC Team and the The Future of Mod API talks.

You can watch the presentation here:

General
The features were:
 * Rewriting rendering engine
 * Will require a higher OpenGL feature-set
 * Will include some sort of fallback for older hardware
 * Support for high resolution textures
 * The internal layout of texture packs will change
 * Every block will have its own texture file
 * Supports the use of animated textures for all blocks
 * The geometry of individual textures can differ
 * Not intended to support HD skins
 * Much faster overall rendering, resulting in more frames per second (FPS).
 * Lighting fixes similar to the ones first introduced in snapshots 12w39a/b (during 1.4 development)
 * Support for fancy lighting control
 * Support for more realistic lighting, such as active furnaces only giving off light from their front surface
 * A new format for 1.5 texture packs

Gameplay

 * Redstone Improvements
 * More predictable and consistent redstone behavior
 * The functionality of BUDs may be affected
 * Eliminating directional quirks
 * Most of the timings of redstone contraptions will change
 * Overall redstone will be more like analog signals
 * Redstone signal strength will matter (for some blocks)
 * New ways of transporting items
 * Using minecarts similarly to Railcraft systems
 * New uses for storage minecarts
 * Fix for many bugs
 * Fix for dropped anvil makes no sound when it breaks
 * Fix for linux users can't open to LAN because it's bound to 127.0.0.1
 * Some Redstone bug fixes
 * Fix for random black spots
 * Fix for some rendering bugs
 * Fix for tile entity crashing bug

Blocks & Items

 * Comparator
 * It is the same as a repeater, but with 2 inputs
 * If input A is stronger or equal to input B, it either repeats the signal or outputs a fresh signal
 * Output is toggleable by right clicking.
 * If input A is weaker than input B, then there is no output.
 * Hopper
 * Trapped Chest
 * Weighted Pressure Plates
 * Outputs a signal with a strength corresponding to the weight of the entity (e.g. storage minecarts) sitting on the pressure plate/detector rail
 * Block of Redstone
 * Nether Quartz Ore
 * Daylight Detector
 * Outputs a signal with a strength corresponding to the angle of the sun
 * Nether Brick Item
 * A Rail for Filling and emptying of storage minecarts
 * The possibility of linking minecarts together (driven by furnace minecarts)
 * Rails to unload mobs and perhaps players when reached

World Generation

 * A new ore in the Nether.
 * For encouraging the exploration in the Nether