RAW files allow for a far higher (potential) dynamic range than normal images, even uncompressed ones, and thus would allow far more flexibility with ToD and weather settings. For evening/night, the darker end of the RAW data could be used, as opposed to daylight where the brighter part of the RAW data could be used. At present the textured materials just get darker and lighter by their shaders. But with RAW, the texture itself could actively change its dynamics to match the lighting conditions. I'm not really sure where I'm going with this, I've had a few and might be talking a big bag of arse, but I feel some kind of discussion about it could be worthwhile.