Oh, you mean Power Stone: Grand Battle RUSH? The game isn't even as good as Power Stone anyway >_>
No anime game is as good as the fighter it's compared to.
As for the generic enemies….
Would you rather run into a jungle and get jumped by Arlong, Crocodile, and Lucci or a bunch of generic pirates? It seems you haven't played any of the OP RPGs then, because they ALL have generic enemies.
Just dudes that do something different is all. I mean all the different types of enemies where too similar in attacks(Basically close range and long range guys If I recall correctly) and look like they are almost no challenge at all.
Besides, One Piece really wasn't made for a fighting game anyway (fights that average 3 chapters, too much variation in ability, etc.)
Are you kidding? Especially after Enies Lobby.
That arc just screams fighting game material.
Also, if you wanted to know, OPUA had more cameos and characters then ALL of the GB games.
I doubt that.
Like the RUSH stage were littered with cameos, like Lafite tap dancing in the training stage, along with the Gorosei, mihawk and Doflamingo just chillin watching you fight. If I recall correctly, a bunch of Black beards crew could be seen walking around in the crowd as well.
I noticed new things in the stages everytime I played.
I won't say you're wrong, since I haven't played GA all the way through(played briefly on my friends japanese wii) but I highly doubt that it has that much. Especially with all the boring forest running I'll be going through.