One Piece, but with a custom character
A simplified but expansive list of options for devil fruits, with the tradeoff of having lower or slower growing haki. One command per button on the controller, for example, for each fruit as well as an awakening mechanic.
Apart from devil fruits, well-developed, but simple and crunchy, class mechanics for a warrior, swashbuckler, swordsman/samurai, sniper, artillerist, cyborg, artificer to make room for playstyles that don’t include devil fruits. Each player would have a class, some would have devil fruits, with tradeoffs in terms of how much you can unlock or develop your class if you have a devil fruit ability.
Open world with a linear story progression and timelines, events and other characters moving in the background.
Storyline of One Piece — of becoming a pirate and going after the One Piece yourself, running across big familiar names in an alternate version of the One Piece narrative, with no Luffy but the Straw Hat crew available as well as other characters for recruitment.
Would be a lot but choosing whether to go into the Navy or be a pirate/bounty hunter would be interesting. Work in the ability to leave the Navy or become a Shichibukai/Yonko and work for the government.
An interactive bounty system, recruitment system, plus a good loot and inventory system would put it over the top.
Essentially, start in Luffy’s position with a customized character and run through the story, making different decisions than he did if you want and seeing the consequences.
Its next console generation at least before anything satisfying could be made. AI could make it attainable but we wouldn’t see a game until 2028 if they started working on it today.