I love this.
Too often artists do not go "too far enough" and end up with a half-hearted expression, but you have absolutely positively pushed Luna's legs to the point where they absolutely the hallmark of the image.
Like Sailor Moon's legs, you're breaking the rules in a beautiful and creative way that really makes this image stand out. The anatomy still "works" and is clearly in keeping with the theme of the show and the original character designs, but also is pushing it, testing out a new horizon without violating the original design's aesthetic.
And the use of a slightly heavier tone on the hooves really grounds the image, and makes the minimal touch on her mane and tail even more light and expressive. The effect is that there is shading, without moving away from the minimalist approach.