So at the moment we have: Lighting engine overhaul. Current engine has some bugs. First introduced in snapshots 12w39a/b (during 1.4 development), Dinnerbone tweeted to revert back and push this to 1.5 The features were: Faster overall lighting system Support for fancy lighting control Support for more realistic lighting, such as active furnaces only giving off light from their front surface
Cause he wanted to steal some of the spotlight from chickeneer also all he did was copy what the wiki said. :S Also yeah the only reason there is already a 1.5 on the wiki is cause they are pushing back the lighting fixes to 1.5 They aren't working on it at the moment that's just whats planned after 1.4 comes out.
That might be fixed in 1.4 the stairs and half slabs lighting glitch. The darkness that forms in caves and such is the one I think they pushed back to 1.5.