well in the first season the story was about finding the damn treasure. everything just developed around it (which is totally fine and i quite liked it that way), but in the following seasons it suddenly wasn't about the treasure anymore. it was only about checking out new places and fighting off random dudes that just appeared to be there and became a threat. and that appeared in every god damn episode i watched. the gang was just on a random place and was fighting with someone that doesn't have anything to do with the treasure or the journey itself. it's like they let a computer throw some dices to write the episodes for them. one dice for how the island will look like and the other for how the enemy will look like. and it didn't matter at all that they win the fight, 'cause they didn't progress their journey at all. in the next episode they were already on a new god damn island just metres away from the last one and ofc were fighting again... episode after episode. sry one piece fans, but that's just how i see the serie. for me it's just milking the serie dry, which is pitty in my eyes, 'cause i did see potential in the story (btw. it's totally fine for me if you like the serie, but i just lost faith in it and began watching other stuff).
by the way, we are talking more about the serie than about the game, aren't we? XD