"But this is Doctor Who. It is, as its heart, a show for kids and family. It should not be protected by some kind of geeky jurisdiction. The Doctor is practically already without gender. The romances are barely that; the sonic screwdriver is not a metaphor for some dude’s wang. If we can’t give the role of a flesh-changing alien to a woman and instead relegate the actresses only to the “girl groupies,” that’s kinda fucked up, isn’t it? What kind of message is that for the families who are watching the show? Not the adult geeks of Whovian fandom, but kids who dig the character and all its assorted fictions?"
So far the opinions I’ve encountered against casting a woman/POC Doctor have amounted to “But the Doctor has always been a skinny white Englishman!” which isn’t even accurate because once he was a skinny Scotsman and another time he was a pudgy Irishman. But even if it were true, how is that remotely relevant to the show? Why should a show about all of time and space be limited by gender or color?
Wendig’s post is really short and still manages to counter every possible argument against making the Doctor a woman (and by extension, a woman of color). Give it a read.