I for one was sort of hoping for a black woman to play the Doctor. Someone similar to Nicki Omuka-Bird (physically at least, I do not know if she's any good outside of the more sober toned serious roles I usually see her play). As to non-white men I had Adrian Lester or Paterson Joseph or Lennie James in mind. I really think Lester was born for the Doctor. Of course I'm one of those who thinks Idris Elba was born to play James Bond,so maybe I just have some crazy casting ideas.
just not as noisy as the "I want a female Doctor" criers.
I think the issue with a female Doctor is that Timelords have been portrayed as being one gender or the other throughout their regenerations... not sure it is an issue with race though and it would make an interesting change.