That was Rey being the new Luke, being the only one who thought Kylo could be redeemed.
Like Luke was the only one who believed Anakin could return from the darkside.
Rey was right by the way they won the war because Ben Solo was redeemed. He saved her from dying and traded his own life.
I guess you could complain they just recycled episodes IV-VI and the Disney movies offered nothing new.
Ben turning to the light restored the Balance.