Let me say that killing Yamato will be dumbest thing that ever happened in One Piece. If she die right that will turn her into plot device. Also if Oda didn't know what to do with her, why she couldn't be more villlainish character who is loyal to her father? We already have heroic death, and that was guy Yasuba, who saved raid planning. Yamato should be ace of beast pirates, but due Oda's stupidiest he made her "Oden". And her death wouldn't redeime her existanse. If she right now will turn into villain, that is your solution. Her death wouldn't have any impact.