In an AU where sunset shimmer stayed and was still celestias student but twilight also became her student. why cant there be two proteges? especially when there both giftedly talented. Twilight still became the wielder of magic and sunset was in the shadow of twilight (remind you of someone?) and twilight becomes princess before sunset, even though sunset has been in her studies long before twilight. but sunset keeps striving. she finally also becomes a princess about a year later. She becomes the princess of Aspiration!! She so long wanted to be like celestia and gather up much knowledge from experience and help other fillies earn there cutie marks (perhaps the cutie mark crusaders?) and they found there destiny! Which crowned her the new princess of equestria.