I think the busy-ness is caused by too much use of light without a clear rule about where it's used. I'd tone down the corner squares from the stark white to something grey or darker. Use the lighter lights like the beige to create the bouncy light squares to add interest. Also, don't put the lights next door to each other (although I'm sure you're planning to move the ones that are so close.). I'd use random placement of the lighter blocks.
You've done excellent work, but I agree. It's not my cup of tea either. But I would ask your friend. If she says she likes it, then it's good.