First let me say I saw your final design, loved it. But I love this even more. And I know people have an opinion about her not having a tiara, I say she's doesn't NEED a tiara. I've seen a LOT of concept designs, but this one is top notch from the theme to the expression.
Allow me to rant for a minute when I say I am frustrated with DC and how they've done Diana over the years. They hit with Superman, they hit with Batman, but they continue to miss with her ESPECIALLY when it comes to costume design. She's a freakin AMAZON, and you have captured that with this concept. Hats off too you, and it's going in my favs.