It would be nice to have colored light. For example, you could set the sunlight to something yellowish, and the sky light to a light blue.
Broville never looked sunnier.
Not only does this mean we can have green glowing radioactive ooze, and caves basking in the deep red glow of magma. The system already supports semi-transparent materials, so we can also have cathedrals with stained glass windows casting colorful light patterns onto the floor, trees with a greenish shadow,....
The downside... it costs yet more memory. It's using 74 KB per chunk at the moment, just for the light map. And there are hundreds of chunks in a scene. Once occlusion culling works properly, it will become difficult to predict just how taxing a given scene will be. I guess I'll have to dynamically change the view distance based on the current frame rate and the memory load.