I'm no interior decorator but I believe the lighter color makes the room look bigger so that blue will look really nice and I too like the darker shelves for exactly the same reason as you ... The richness!!! As you know I too have doors on my toy cupboards. I like being able to use that as toy rotation. So I think is you have light colors accents ... Pillows, throw rugs ect it won't make the room look too small. That's my nickel ; )