This got me thinking. If Ben is redeemed, I think it would make sense if the saber went to him. Ben accepting and turning it on would be a powerful visual, showing his turn to the light and perhaps remind us of the scene where Luke gets the saber from Obi-Wan, with unknown adventures ahead. It would symbolize the hero and the Skywalker within him. “It belongs to me” would get a new meaning. The saber being broken but repaired would of course symbolize Ben himself, especially since it was repaired by Rey much like Ben might be. Rey handing the saber to Ben would be a callback to her handing it to Luke, and Ben accepting it would symbolize him giving Rey the belonging she was searching for in Luke. “It belongs to you”, she might say, tying their story arches together.
That would be pretty great and epic if you ask me.