I like the elemental theme (+1), I am not to familiar with this commander I decided to go with Sliver Queen for my 5 color deck and I am toying with the idea of building a Scion of ur dragon deck as well.
I would tell you to add Ashling the Pilgrim but that is just because I love her. I built a deck around her so my opinion is a bit biased. ;)
Feel free to check out my creatureless Ashling burn deck if you are curious. Ashling's Apocalypse