7. He Is The Valeyard
The Valeyard appeared during the 6th Doctor's reign, in the story 'Trial of a Time Lord". You may want to stone me, but I haven't actually seen these episodes so I am relying on the collective information hub known as "the internet" for this info. The Valeyard was a possible future version of the Doctor, somewhere in his last regenerations. He was thought destroyed, but briefly shown to have survived at the end of the episode. Doctor Hurt could be another incarnation of the Valeyard. This would jibe with why he hasn't been referenced as the Doctor up to this point and also why Doctor 11 recognizes him, as he has encountered the Valeyard in his 6th body. Likelihood? Sure, why not... This could launch a new villain to outwit, and that is not without precedence in the new show. The Master and other Time Lords have returned, so it would not be a huge leap to think that the Valeyard could return as well. Not very surprising or original, but sometimes it is nice to tie things up with the older series.