Is this a glimpse of the future disguised as a past from the past? 9 years ago, Steven Moffat said:
"Although I loved Peter Davison and Paul McGann, probably the best two actors in the role, I don't think young, dashing Doctors are right at all. He should be 40-plus and weird-looking - the kind of wacky grandfather kids know on sight to be secretly one of them (Doctor Who - Online Magazine & Fan Site)."
Let's choose to ignore the Paul McGann thing, I agree about Peter Davison, and I would add Tom Baker to that list. Since he in in charge of the series now, if Steven Moffat still believes this, it rules out all of the names who have been rumored to be the next Doctor Who.