I love the colors and think it will look great when finished. In addition to the bottom right that needs a fix to the layout, I think what might be throwing you off is that the last row creates 1/2 the design. I am funny about things being symmetrical, so if it were mine, I'd take that last vertical row and add it to the bottom, which would create a more symmetrical design and really show off the "rings" that the individual blocks form.
If you still don't like the look, add a solid inner border of the same fabric you used for background and an outer border that isn't too busy. That will help tone it down for you.