I would honestly love to see a chapter or two dedicated to each SH at these ages once One Piece is over. See in which ways they have matured, how they interact with others, how and to what extent they still interact with each other, what they are up to, and so on.
I think it would go a long way in giving us the feeling that we've kept up with them and their lives, and if we get these after One Piece is over and we know there's no "next weekly chapter" to look forward to, it would be content that would be really treasured by the community.