if she were a full recolor the cutie mark of Twilight would be on her and not a different one. they made her similar cause she was bff with Twilight and some bff's copycat each other in looks and other ways and they wanted the fans to have the drawing line of how Twilight would be like the moon dancer we meet in the episode if Twilight never met the mane 6 and continued to further herself from other ponies and never opened up to others.