10 'What Ifs' That Could Have Changed The Course Of Doctor Who
1. William Hartnell Never Fell Ill
The decision to recast the same character with an in-universe explanation of the change was probably the most iconic light bulb moment in television history. William Hartnell, the original Doctor, wasn't exactly running on all cylinders throughout his run in the TARDIS. As the years rolled on, he became less reliable, flubbing his lines and generally looking exhausted.
But what if Hartnell remained fit as a fiddle all throughout his run, and beyond? The concept of regeneration wouldn't have been devised, the show could have run dry with a singular characterisation of the Doctor at the helm, and it might not have made it as far as 1989, let alone be rebooted in 2005. As much as it was a painful pill for Hartnell to swallow back in 1966, it was a necessary move that laid the groundwork for Doctor Who to become the worldwide phenomenon it is today.