"When the certain someone shows up after crossing through 800 years"
My honest wish is that the sentence is LITERAL, and Joyboy traveled and time-jumped into 800 years into the future. Rather than the famous idea of Luffy being the "New Joyboy"
Instead, I'd much prefer if "Joyboy" the original one will actually show up. And it's just like Oden said "he crossed through 800 years"
And he chose this timeline, based on a seer he had "Just like Madam Sharly", telling him that their plan can only work in 800 years. Which is simply because it's the timeline where every corner stone is in the right place and awakened.
meaning, I'd rather change the whole concept of:
"Luffy is promised person, with prophecy who will inherit Joyboy will, and it's fated that he will create a gigcantic war, and win and overthrow corruption, it's fated, it's going to happen no matter what"
INTO a new concept which is
"Joyboy and co, are fated to LOSE at each timeline they go to, but the ONLY timeline, where everything can be fallen in the right place, to actually have a chance of Victory, Luffy and SH being there, Poseidon being awakened, Pluton, Uranos....etc" The only timeline where they can FIGHT AGAINST THEIR DESTINED FAILURE is this timeline. And Joyboy is traveling by Time Fruit into the present, and will show up soon.
So, what I'd rather have SHs at our side be the "Underdog" here, and them fighting against "Fate/Destiny" of Losing. Than have them "Destined to win" and Luffy being "New Joyboy"
I hope my explanation makes some sense.
Also, it would go hand in hand with those ideas:
1- D clan having a chekered life
2- Celestial Dragons are the Gods, and D are opposing god and their destiny
and so on and on for other ideas