It's pretty simple, if you want to make a movie with a black guy or a woman or a black women or whoever else, go for it. Create a new IP, write a story, make a good movie, and people will watch it. Don't take an existing IP and replace the established main character just so you can check boxes and score points with the people. They don't do these things to be innovative or for any reason other than being able to say they did it.
Dr Who is different because, unless I'm mistaken, in that universe the "Doctor" is reincarnated as different people, right? I've never seen it but that's my understanding from what I've heard and if that's true then I can understand being reincarnated as a different race/gender. On the other hand, James Bond is a white guy... changing that doesn't make any sense. Just like it wouldn't make sense to suddenly have these movies without James Bond. Just find a new Bond, as they always have, make new movies, and if you want you can write a spin-off in that universe with other agents and make them whatever race/gender you want.
TLDR: Add, don't replace.