Thanks, Rafael. I didn't really change all that much -- talked to some video folks that I work with, and they though it looked great for youtube, so mostly I just stopped worrying. I did change the background color and exported to 1280 x 720 pngs, which helped some. It's the blue that looks the worst, and there was a lot of that in the sample I posted earlier (doesn't contrast w/the edges enough). It still looks a lot better on my computer or on drop box, but oh well.
I do appreciate your help -- definitely got me to try different things, and to get unstuck.
ps -- thumbnail seems to have updated.... hope someday I get to pick, as there are still much better choices.