Only that it isn't only "professional review" that are saying it's a bland game. Even fellow gamers that I've come across on various gaming forums, who have played the PSP version and the 3DS japanese version have said the same thing. Look, I'm a pretty big One Piece fan myself and I'm not looking at it through rose-colored glasses. I've seen various gameplay videos and other reactions and have seen all of the problems people have described. It does look bland (endless, boring corridors with lite rpg elements).
That being said, I'm sure there are people out there who will enjoy the game. I'm still hesitant to get it or not. But I'm not sweating it. Because it's also being released on the eshop, there is always that option in case I do change my mind in the future (if physical copies to sell out quickly because of how niche this game will be).
It's true that the eShop version is there for people that are okay with having digital copies of there games, I myself prefer to have a physical copy, and I'm enough of a One Piece fan to want to support any releases the franchise gets in the West, especially when it comes to video games since we tend to get skipped over for a vast majority of them.
As far as the game being bad, I haven't really done any research on it, honestly, when it comes to games I really only care what I think about it, not what any other reviewers or fans things, so if I get burned on it that's my own problem. I can respect that people may not like the game and don't want to waste there money, however I'd just like to see the franchise get the support it deserves since it's typically overshadowed here in the West by other more popular franchises.