The above photo shows all the fifteen incarnations of Doctor Who. The show has been on air for the past 60 years, excluding a brief ten-year hiatus. What has kept the show alive for such a long time may very well be the brilliance of its premise. That is, whenever the Doctor dies, the character simply regenerates into a new body, a new Tardis, and new companions. Out with the old, in with the new, so to speak. However, if you take another look at the photo above, you will notice that Doctor Who just broke that premise.
David Tennant, who played the Doctor from 2005 to 2010, has returned as the Fourteenth Doctor. This was originally planned with Tennant returning for a special and then, during that special, he would morph into the Fifteenth Doctor, stripping away his old self, and living on as the new one, which will be played by Ncuti Gatwa.
This is where the show pulled an unexpected plot twist on everyone, which some argue may be ruining Doctor Who's premise altogether. Instead of dying off and passing the baton to Gatwa's Doctor, Tennant's Doctor split into two, Tennant and Gatwa, essentially saying that Tennant's Doctor will exist simultaneously with Gatwa's.
As Gatwa's Doctor goes on adventures, Tennant's will just be living in suburbia, like any retired person. Some may regard this move similar to the MCU's multiverse, and perhaps, moving toward that direction may stir some fans' nostalgia for previous doctors, and possible cameo appearances.
Some argue that the concept of regeneration and leaving the past behind is one that has been the cornerstone of Doctor Who, and trying to change that now, just seems self-indulgent. Although I doubt people will stop watching the show simply because it decided it's time to alter its premise.
(Image credit: BBC/Wikimedia Commons)