I’ve voted I don’t really have any strong feelings either way, though this isn’t quite where I sit. Ideally I think the Doctor should remain a man, however I’m not completely intransient in this view. As diankra says it really comes down to if someone can play the part.
Get the right actress who’s given the material and I think it’ll work just fine. What I don’t want is for it to be done for the sake of it. As Matt Smith just stood out in the audition process, if Olivia Colman or Nicola Walker or whoever did likewise during the audition process then I’d rather they got the job than be overlooked just because they’re in a skirt. But, and a big but, I don’t want the best candidate to be overlooked because they aren’t in a skirt either!
The same is true and ethnicity and age too.