Interesting abstract piece deridor!
although it seems a bit over-complicated for the level of detail in rendering.
Since it's a purely black background, the lights don't need to be nearly that bright to create a magical effect, I'd tone them down a bit.
a simple HDRI sphere (even without GI) would make this scene a lot better, even if the camera doesn't see it, simply because it appears the spheres are reflective, but without a proper HDRI mapped sphere around the scene, the reflections won't be able to achieve the level of realism that could make this render so much better.
If you don't mind, I'd like to take this onto my computer, change some things, and present how I would render it.