I also think it might have something to do with when I was born. As great as the Disney princesses are today, I am watching them as an adult, and the characters/films that are most precious to me are the ones I watched as a child, and are unlikely to be replaced.
I have enjoyed watching Princess Elsa and Princess Anna (Frozen) from the bedazzled eyes of my daughter, who was 5 at the time the movie was released. I truly wished magic was real for the sake of my daughter. But thankfully she has quickly grown out of the princess phase. I like the Princesses too because they have a strong bond of sisterhood. I loved the fact that the "act of true love" is one sister trying to save the life of the other.