Rather than being fearful and insecure about her powers, Elsa would have used her powers very hostilely and evilly against others. This would have affected Anna in particular, as she would have been particularly jealous of her given the royal status she holds.
Kristen Anderson-Lopez, the film’s songwriter, mentioned in a 2014 interview that Elsa’s motivation in the film was to freeze Anna’s heart in order to take over the kingdom.
Producer Peter Del Vecho recounted in a 2017 interview that Elsa originally had no connection with Anna and that she was originally a scorned woman who was left alone by her would-be fiancé on her own wedding day and froze her own heart to never love again .
She would have been misinterpreted as “Arendelle’s curse” in the original prophecy and would have saved herself at the last minute to save Arendelle from an avalanche caused by Prince Hans (the true curse of Arendelle in the prophecy).
