Real talk: One Piece has a vague overall goal for the characters, which is to find whatever 'One Piece' is. The whole show has a target destination, even if it does meander for a long time. And most of the cast stays consistent, albeit with development and growth. They'll come and go each season, and there is a certain focus on continuity.

Doctor Who's about a character wandering about with no singular objective, aside from whatever arch the season may have (and it usually just matters in the season's end). It has a supporting cast that changes after some time, with the old ones rarely returning. And the main character literally changes personalities and looks after a few seasons. Continuity is as wibbly-wobbly as how the show treats time travel.

So no, they're not actually the same. The only comparison you can make is the f*ckton of episodes each show has.

No, it's british jojo.
The protagonist changes all the time and god know where the overarching plot is going.