I think it needs some lovely quilting in the white areas & a pretty teal binding on it -- nothing else. Your blocks are beautiful & the overall look is perfect for a young modern-transitional decor. You didn't say whether you're planning on quilting it yourself or sending it out, so I won't offer quilting suggestions, but there are plenty of lovely ways to add interest to the runner with the quilting (anywhere from basic lines to circles & feathers) in the white areas that I think would give it that pop & separation it sounds like you're seeking. My personal opinion is that adding sashing around the blocks, especially dark colors, might not fit so well with a young person's decor. I'm hoping to paint my own kitchen cabinets that beautiful aquamarine color that's very on trend right now & would be thrilled with the piecing exactly as you have it right now.
