3. The Trio of Doctors Were Perfectly Matched
The Doctor, like any other person, loves and hates himself in equal turns. To have three different versions of oneself running amok , in hopes that the world will somehow be sorted in the end, is a recipe for chaos. And yet, the disarray was extremely limited with the three faces of The Doctor united against the forces of evil. What will start as bickering and confusion will eventually turn into serious conversation, which will then turn into eventual and mutual resolution of the problem at hand. Steven Moffat's writing lends itself to such conflict resolution on a regular basis, but having the trio of Hurt, Tennant, and Smith only helps additionally sell the concept. Hurt's War Doctor is the remnants of a time when The Doctor mostly took on the form of an older man who was to be trusted and didn't run around wildly gesticulating. Tennant and Smith, on the other hand, represent a gradual devolution into someone that runs round with an enthusiastic, child like persona but at the same time encounters some serious grief that they usually don't let themselves off the hook of too easily. Having Hurt's incarnation around, the other two realize just what is needed to alleviate themselves of the burden they've been carrying around for so long and Hurt realizes that he doesn't need to go against his moral code to save the day. With the balance of personalities in effect, the Doctors decide to not make the mistake of wiping out Gallifrey, which in turn spares them from the depression that decision led them into afterwards.