You don't reckon it IS McCoy, do you? That The Master has found some way to regenerate in the forms of previous incarnations of The Doctor?
Cool idea, but McCoy as a scary Master does not work for me. To bad we could not get Derek Jacobi back as the master.
Why would McCoy know? Is Steven Moffat ringing him up and spilling all the beans? Not proven, insofar as I'm concerned.
Folks do natter behind the scenes at cons and signings, but that's why I think he's referring to the Master And Commander fan-spec.
In some respets Dance would be perfect, in others he's a bit obvious (and I don't mean that in a bad way but I'd just expect a little bit more left field choice) Also whilst on one hand the notion of the Master taking over Galifray makes sense, on the other hand it doesn't given the Timelords have likely just deposed one dictator in Rassilon (although who knows how quickly time is passing for them.) you'd think they'd know better than to replace him with The Master?
On a similar note, how and why did Peter Davison know the regeneration limit would be dealt with in Time of the Doctor? I seem to remember sometime in the fall Davison revealed the limit would be dealt with saying something like "people haven't been counting regenerations properly." Yeah, I know, it doesn't prove this story is true, but it does create a possibility.
On the subject of The Master, I heard that Michael Smiley (http://www.imdb.com/name/nm0806968/?ref_=nv_sr_1) was under consideration. There was little to back it up and I think it probably just stems from the fact that he was in A Field in England, whose director, Ben Wheatley, is directing some of the next season. He'd be an interesting choice though.
Ooh now Smiley's the kind of choice I'd call left field (in a good way). Good actor, can be very scary too.
Well, that explains Tom Baker in the 50th. Gives the Doctor advice that leads almost directly to his regeneration....what a jerk But then again, who knows, who knows...
Nah, I think the McGann tweeted Pic makes it pretty obvious, when coupled with Sylvester McCoy's comments, that it's actually McGann, who will be the Master (The Curator wearing Tom's face was foreshadowing)