I would add a border with something to "quiet down" the dark browns, blacks. Maybe a Gold and Blue together with something that speaks of "this is the end." As it is, it is beautiful, but I don't think it would be relaxing to look at for very long with all such strong colors. With something like the gold and blues, it would give good contrast, and also speak of being completed. Mariah.

I have never attempted a round robin before. I did not join in the RR when my quilting group was doing one, so I'm afraid I will not be much help. However here is my two cents for about all it will be worth. lol I think the outer borders are so dark, it all takes away from the center block. I think I would add two flange sections first one in blue and the next one in gold or bright yellow as if everything were going into the sky and then to the sunn, (blue representing the blue sky and bright yellow the sun) I guess this doesn't make much sense. I think I would personally make the flanges about 1/2" each.
I am currently working on a challenge quilt of black & white, but for the challenge we need to add a color to pop. I did not want much of another color, so I made three flange sections 1/4" each with black then my pop color burnt orange, then black again and added the final border to the quilt. I really like how this has turned out. just enough color to satisfy everyone I think. Perhaps something like this if you can make sense of what I am talking about.
Be sure to post final picture please.

Well ladies, I tried all your suggestions and finally settled on a yellow/beige batik border that had oranges and blues through out it. I just did a plain border as everything I put on it to try to balance it seemed to make it feel one sided more.

The one that was returned to me though turned out goregous!

Now here's the art in me and it doesn't follow the RR rules. Put a wavy row of flying geese in blue sky with yellow birds going through the left and top areas of the quilt.