I'm a big One Piece fan but i wasn't super into this one.
It tried a bunch of things, all of them half baked. The exploration mechanics were neat and it was fun to zoom around the map, but the map was way smaller than they made it out to be.
I didn't much care for the story but i liked that the Admirals were involved and you got to fight them.
This game was at least good if you wanted to experience Gear 4, but now Pirate Warriors 4 lets you do that much much better.
It's good enough for one playthrough.