Well the show's style displays the ponies with quite round heads, with a little addition for the nose/mouth-part. I just feel like Rarity's head is a bit too big above her horn, making it look a bit egg-shaped. [link] here you got the shape quite perfect in my eyes. Of course Rarity doesn't have bangs so her head is seen kind of "naked" in this pose which makes the form of the head even more visible, but when I look at this picture and imagine her head's shape a bit different, it instantly becomes much more beautiful.I really don't mean to insult you, just offer some critiqueMaybe it's just me because the other commenters didn't seem to mind.