John Hurt is off the list!
At the end of Episode 13 of Season 7 - "The Name of the Doctor" they introduced John Hurt as the Doctor.
Doctor Who canon maintains there can only be 12 regenerations of a Time Lord, for a total of 13 lives (the 1st one being the one where he is born, not a regeneration).
So if what we are seeing is not some story skullduggery...John Hurt is the LAST doctor. The result of the final regeneration. Which leaves us one more Doctor to fit between Matt Smith and John Hurt.
That being said, we can conclude that John Hurt is NOT the next incarnation, so he's off the list.