How can something that hasnt even been written "not make sense"?
For all you know a story could ne written that makes a hell of a lot of sense, and if you think making The Doctor a woman would add nothing to the franchise just shows how closed minded you are.
Changing the Doctors sex would add just as much, if not more than changing it from one white male actor to another actor.
If written properly it would make more sense and maybe actual push the writers to not just rely on generic stories that are solved by a sonic screwdriver.

Using the white male Doctor everytime is a comfort zone.

Its quite funny how you can accept that an actor you dont know, would bring something to the role but you cant accept that a major shakeup of the character would bring absolutely nothing to the character, especially when you note that she is a talented actress!

Closed mindedness is a funny thing, especially when you have accused other people of similar things when the didnt accept a major comic book character change, and that was after it happened and was judged of something that someone had actually read!

What it boils down to is that you have an idea of what the Doctor should be, and anything that doesnt fit into your "ideal" just isnt gonna work!