Most of the points I would give it are for it's cultural impact on the manga community.
So no matter what I rate it, even if it's a 10/10, at least 5 of those points would be because of the hype/excitement Oda created, iconic characters, merchandise, memories and even it's knock on impact in promoting other manga/anime content as well as the money generated.
Modern animanga would not exist in it's current form without one piece, dbz and naruto which would be a shame. The story telling, character design and artwork on one piece is not even in my top 10 (maybe character design), but for most intents I appreciate it for what it did for the industry so has to be 10.