I never really noticed before, but looking at the show, she DOES have a bit of a flat muzzle. Anyway, right now I'm just looking for flaws because this picture is easily more attractive than not. I'm looking at shading because it looks like you've done it very well. I do wonder why her saddle seems to shine near her flank, yet her flank immediately under her armor looks shaded. It doesn't look like her armor is thick enough or hangs over her back leg to cause that shading. Other than that, the shading consistently looks like the lighting is everywhere above her and looks great. Her irises looks pretty and her eye shapes and sizes are consistent with the show.
I like the way you used your colors. It's apparent on her saddle and the background that your colors are layered, but it looks very nice. I do think it's a bit odd that the hair on one side of her horn is still "with" the hair on the other side of her horn, but that only came to question because I was admiring it. The slight translucency of her wings looks done well, and the shape of her legs and body are as consistent with the show as the rest of her.
Overall this is a pretty picture of the character. I won't give a lot of originality because she's the same style and it's just a colored background. The lack of a specific background also takes away from vision and impact, but it does still look pretty. It's not a new style or take on her, but it's a great looking remake with very nice shading.
Well for me, it didn't do much for me. I just don't like those type of villain songs where the villain is all victorious while the heroes are down on their luck. It just makes me wanna go up to the villain and punch him/her in the face.
But I respect your opinion so I won't stop you from liking it. Sounds fair, right?