"...This is important for the same reason his education of Leela was, and training Sarah Jane so someday she can fill his shoes protecting Earth, and completing Adric's impressive Maths skill with advanced technical know-how turning him into a true boy genius, and even obtaining The Master's (if treacherous) help to save the Universe from Entropy, having Nyssa help him recover his normal size after the miscalculations induced by the rogue Time Lord and getting bossy Tegan to stay back to help him in Logopolis, even without having to ask her. The Doctor is a hero in many ways, he saves people, worlds and times, and he risks himself to save others. But, as Russell T. Davies says (and director Graeme Harper agrees):
“The most important thing for me about the Doctor, is that he is an enabler. (…) More often than not, he enables the “little man”, the innocent who is the victim or is affected by what happens in the story, to help himself. With the Doctor as back-up, using his fast brain and abstract ideas, he enables him to become heroic. The Doctor presses the right buttons to enable the little man to become marvellous and save the day”(Russell T. Davies on Graeme Harper, Calling the Shots. Directing the new series of Doctor Who (Surrey: Reynolds & Hearn, 2007))
The Fourth Doctor has made the transition from hero-of-the-day (look at his relaxed demeanor at his first serial, Robot, while very secret material is being stolen from UNIT’s advanced laboratories, only to later prove his Holmesian deductive reasoning) to enabler. "