Oda doesn't really need to do that though. Do you really think he wants everyone talking about the next nakama if there isn't going to be one? Is his goal to dissapoint his fans? People will talk endlessly about One Piece anyway.
Wanting to join the crew and then moving away from it was part of Yamato's arc. A poorly written arc that goes against One Piece's usual philosophy, but it is what it is. I don't see any point in making Luffy invite Loki like that, especially with him saying no at first like all the members who actually joined.