SPOILER! possibly... just seen a still of Hurt online, seems to be wearing Mcganns costume with ecclestones jacket over the top? Instead of a future Dr, could he be a lost incarnation? Somewhere between Mcgann and Eccleston? That would make him the ninth dr and ecclestone the 10th? Weird twist if I'm right. Pity not bringing Mcgann back as well to regenerate into him, then Hurt regenerate into ecclestone...that would be something! Could all be linked to the dreadful events of the Time war
Or of course he could be an older version of Mcganns dr, but in that case he should be played by Mcgann! To recast an existing living dr is unforgiveable bad manners, hope its not been done to just catch a bigger star for the role. Would much prefer to have Mcgann back as he is a real dr, not someone shoe-horned into the part. and if they wanted him aged,there is such a thing as makeup, look at tennant in the sound of drums etc