Ohvist
There should have been a more interesting element if Rarity actually was a Crystal Pony instead of an Equestrian Unicorn. It’s highly unlikely that when King Sombra banished The Empire into the future, not all of the Crystal Ponies were inside of the city limits at the time: that there were a few who fled the city limits and approached the Royal Sisters for aid. If not, than how would you explain the existence of Princess Cadence, the last of the Imperial Family who was found as a child in Equestria?
There should have been elements of the story talking about Crystal Pony Refugees struggling to reintegrate with the Empire due to how many generations separating their descendants that have lived in Equestria all this time, or alternatively that the Imperial Refugees were treated poorly during Celestia’s solo regime or were completely ignored in all that time allowing for corrupt Nobles to perform twisted machinations on the Refugees without anyone either knowing or caring about it that it caused a number of these Crystal Ponies to lash out at Equestria for their pain and humiliation and anger.