look, when you remember how lazy OP game developers can be sometimes, there's no help but to be afraid that they are going to pull some dumb moves, like…remember when only Luffy was usable during Story Mode of PW1? or when in One Piece Gigant Battle I you couldn't play as Robin, Franky or Brook but just use them as Support characters?
so when I read that this game supports only one player and that it's going to be from "Luffy's point of view" all this backstory comes to mind. Sure, it's waaaay to early to judge anything, but it isn't a promising start for the "dream game" of One Piece. Personally, I don't buy much into developers words, but this was such a setback that I was kinda shocked.
Anyhow, waiting for more news. This suggestion in the Siliconera's article that you are a character linked to Luffy opens up the idea of customization, which is neat.