Who indeed
And the show *is* called Doctor Who, not Rose.
This is something people keep pointing out, often mingled with displeasure at Rose’s prominence.
Thing is, the title is a question. It’s not called “The Doctor” or “The Amazing Adventures of the Doctor” or “The Doctor Saves the Day”. It’s called “Who the Hell Is This Guy?”. And for that to be the title, the implication is that the focus will be on whoever’s doing the asking — on the impression the Doctor makes on said inquirer. Rose’s role was to act as the audience’s eyes and voice, to explore and maybe to some extent answer the question — though even at the end she never really got a full answer. And we probably never will! He’s the enigma at the center of the series; his companions are in effect the protagonists.