Doctor Who has always been a series about change. The show has become one of the longest running sci-fi TV series in history, thanks to its ability to keep changing and moving forward, with the series itself regenerating along with its main character. This unique adaptability has seen Doctor Who thrive in the hands of countless writers, producers, and actors. However, not every change the series has undergone has proved popular with fans. Despite 60 years of regenerating, redesigning and re-imagining the world of Doctor Who, major new additions to the series' lore have often been met with backlash and controversy from the fan base.
Source：https://www.cbr.com/doctor-who-bigeneration-controversial/
