You could take any of the Doctors (well, maybe not McCoy), line them up in a row and extract something great from each of their performances. One thing that remains true with each incarnation, however, is the moralistic and peaceful approach of his methods. Employing weaponry as only a last resort, the Doctor has worked tirelessly to save the universe, despite all of his greater losses.
On top of this, he has thirteen chances at life, and two hearts. After a thorough look at the enemies he’s faced and defeated over the years (from the Daleks to the Cheetah People), it would be silly to deny him hero status.