This is an amazing piece.
I love how you made Luna slightly mysterious, it works well for who she is and what she's like. And also works well with how you made Celestia far more "open" and more... I'm not really sure how to describe it? Me failing to convert meanings into words again. Oh well. I love both pictures. But particularly this one. (Partly cause Biases... All hails the luna republic.
Luna is best pony!)