Hey, not really a crit, just a pointer: I'd not focus on Lensflares right now or anything. Although it makes a lot of the Concept, the important part should be getting all and every detail in diffuse down first and then worry about lens artifacts and flares.
Well a the smartest thing is not to have every cube as a separate object, since the cubes only render in one area it's not really a problem if the bounding box is big, it's being culled when you leave the area or with frustrum culling if you're not even looking at it. If all cubes are one object, then it's 2 materials with…