2. A Bad Turn For The Doctor
He's done it before-sort of. In 'Matrix' we're shown a timeline in which the Valeyard has used the Dark Matrix to corrupt the First Doctor and several of his future incarnations. As events unfold here the Doctor does indeed leave Gallifrey but with the added caveat that he's murdered several of his own kind to do so- not quite the dear grandfather Susan presents him as in the proper order of things perhaps. And if anyone could give full monstrous voice to this new badboy its David Bradley. Consider his aforementioned roles as Solomon and Mr Filch and it isn't such a mad idea. Enterprising writers could quite easily have him travelling to the Stone Age and ignoring Ian's attempt to stop him whacking that caveman, possibly even going so far as to kill him in cold blood. His destiny as a villain would be set. The Daleks would be justified in their longstanding apparent fear of him and whole armies really would leg it the minute they heard that whirring noise heralding the arrival of the TARDIS. To them it would spell only death. And there's the fascinating possible arc of him seeking, finding and then attempting to kill off his future selves in a display of dominance, seeking to ensure his legacy as the First and only of the Doctors. Round about the time of 'The Man In The Velvet Mask' he's presented as being terrified at the prospect of regenerating and could easily turn his fear to raging anger in a heartbeat. Something for David to really sink his teeth into and potentially run with to chilling effect.