This movie is kind of a mixed bag. A lot of it is good fun, but the first half where they just start off by throwing the viewers into the middle of the story with a bunch of random action scenes, a fruity dance number introducing the main villain, and then flashing back to how all this nonsense with Shiki started felt disjointed and made it hard to care about what was going on.
You're just sitting through a bunch of typical One Piece wackiness without anything compelling to draw you in until the drama sets in later on.
Nami could have done more instead of just being the damsel in distress too, but oh well.