The great thing about the Dr Who format is that it allows almost any type of story. Star Trek is close in format terms and in the early series in particular they covered some quite interesting topics. One early Star Trek I rewatched recently concerned the moral issues of a guy in charge of a colony of 8000 with only enough supplies to feed 4000. He was regarded as a mass murderer and punished accordingly but he made the case that if he had not acted almost all 8000 would have died. How can that be more moral? While I haven't watched many later series of Star Trek, none of those I have seen dealt with such weighty matters.

There have been similar thoughtful Doctor Who episodes and picking some from the Tennant era I would highlight his discussion with the Slithereen and the vampires in venice on how his actions end complete species and does he have that right; the second one I'd highlight would be his discussion on how his regeneration is like death. Reflections on a personal experience of endings of all kinds were fairly common in that era.

Much more interesting to my mind than the staple warring of much of aci-fi