So I was thinking about moving the weapon into the center, for simplicity and aesthetics. You could also justify a beam of light from above better that way.
That way, when the shadow is unleashed it can go directly out (as a smoke trail, shock wave, whatever) to the surrounding worlds.
Also, it might be cool to have a second floor or walkway that surrounds the main area. I noticed in most cathedrals/temples that the lower level is usually solid, and the windows- especially stained glass- is well above head height and out of reach... could also help a lot with the lighting.