For the better part of 60 years, “Doctor Who” has been typified by an ongoing cycle of death and rebirth. The death of one Doctor brought the birth of the next. Viewers of the long-running BBC series instinctively knew from the moment a new actor was announced as the titular Time Lord that an emotional farewell awaited in the not-too-distant future.
That all changed this year, fundamentally — perhaps irrevocably — altering the franchise with it.
Regeneration — one of the most brilliant storytelling devices in TV history — was a gambit born of necessity by the “Doctor Who” brain trust in 1966 when star William Hartnell, suffering from ill health and memory problems, decided to bow out of the successful series after three years.