The early Doctor Who (canonical incarnations one to seven - from William Hartnell to Sylvester McCoy) was a wizard - but the revived Doctor Who is a superhero.
This shows itself in many way, but mostly in relation to sex: a wizard is celibate and asexual - the revived Doctor is sexually-interested and sometimes has girlfriends - even a wife.
Obviously a wizard cannot be married!
Think of the great wizards: Merlin, Gandalf, Dumbledore, Getafix...is it imaginable that any had a wife?
Equally, they cannot have a girlfriend nor indeed any kind of sexual infatuation; and if they do, then they will be punished and lose their powers - if they do not repent.
Think Merlin and Nimue - which got him imprisoned in an oak tree/ crystal cave; think Dumbledore and Grindlewald - which led to the death of his sister but then repentance.
The new Doctor Who is all about smutty innuendos, snogging, declarations of undying love to (serial) companions, besotted companions, and so on - that is the stuff of superheroes.
The sex prohibition for wizards is absolutely non-negotiable, because we are dealing with an archetype: a basic, universal, fixed, symbolic figure.
However, in making the Doctor a sexual being, he has changed archetype: the revived Doctor Who is now a warrior, not a wizard - because the superhero is a version of the warrior archetype.
Warriors are, of course, exactly the kind of people to have a string of (ahem) 'girlfriends' and to become the objects of sexual infatuation like the revived Doctor.
So with the revived Doctor Who we have gone from Merlin to Lancelot, from Gandalf to Boromir, from Dumbledore to Sirius Black, and from Getafix to Asterix (sort of...).
A poor exchange, in my opinion.