I think repeating the rays ties the two quilts together, and since they are soon-to-be-new siblings that's kind of neat!

Thanks for all the suggestions you guys! Hopefully I will be able to come up with something good for this one. I especially feel bad because Emma sees her brothers blanket all around and keeps trying to curl up in it...so this has to get done before the kids are old enough for Blanket Wars!

I would echo around the sun rays

This was my first thought... echo stitch, at least the bigger rays, every two inches or so until you have done all the blank area willl stand! It is a delightful design!