I like the applique. It adds to the overall effect, IMHO. But I would add a second red border outside the appliqued border, just not quite as wide as the first red border. I think this will frame the applique area, giving it more definition.

Beautiful blocks, let them shine on their own!!!

I think leaving the quilt plain is the way to go. Those blocks are beautiful and they ill be lost if you add more applique; the beauty of the blocks will be compromised.