eli0s - that is an excellent demo video, great job. The trouble is there really is a huge amount of features proposed in it! It amounts to considerably redesigning large parts of the engine to get that kind of workflow. So I don't think there is much we can do until some time after C3's release. I do like the ideas a lot though.
I do think its one disadvantage is there is too much built-in stuff happening. For example as it stands now, you can apply effects to the shadows, modify the appearance of the sprite for the light radius, and even use custom light blending by changing the layer effects being used. In your demo the light is basically acting like an entire layer, but with fewer features. We've always tried to avoid this kind of "cookie cutter" approach where you can only have it one way or not at all. So I think the best approach is to have something like what is in your video, but still using the "lighting layer" system. This probably also involves nested layers, but I think they have several other uses outside of lighting, so that would be good to add anyway. A lighting layer also allows a general-purpose approach to lighting - there could even be other plugins that can draw lights in different ways.