Tee that would make a lot of sense. Either him or I could see Ben Daniels being a good Master/ other baddie, too.
The WHO team likes to misdirect, needs to really, in these days of t'interweb, spoilers and social media, so I could imagine that Capaldi and/or Daniels are involved but not as the Doctor.
It's almost like in the run up to the announcement you look at all the red herrings and have to say, no, it's not him!
Bunny, Andrew Scott certainly fits the Moff link in terms of getting the job - he is just such a good baddie, though, it almost seems a shame to have him as the Doctor 
On top of which, he may well yet be in future eps of Sherlock.
I've always thought that if Sherlock could survive the fall at Reichenbach so could Moriarty and the way the TV series played it, he could easily have been faking Sherlock, just as Sherlock faked his own death. In fact, I thought the whole exchange about them being the same seemed to allude to this. And none of the characters alluded to Moriarty's death in the aftermath. IMHO, they've set it up so that Sherlock played out the whole confession to Watson knowing that Moriarty was listening and then took the fall, literally, knowing that Moriarty would believe he had succeeded and therefore he would call off his hounds.
So that's why I think the Doctor may not be Andrew Scott, as he'll be back in Sherlock
