Doctor Who Theory: Why We Won't Meet The 14th Doctor Until The 60th Anniversary
1. It's A Terrible Time To Introduce A New Doctor
This might not be a popular opinion, but introducing a new Doctor to take the lead for the 60th anniversary could be a bad idea.
Ask yourself, what do you want to see in a Doctor Who anniversary special? Likely the popular answers include returning Doctors, companions, villains and a universal-reaching threat.
We know from Davies' previous time on the show that he loves nostalgia and ensemble casting for his 'big' episodes, so no-one's expecting him to shy away for the 60th. Throw all of those factors into the mix and you've got a lot to fit into 60-90 minutes.
Is it a good idea to put the spotlight on a brand new Doctor in that same mix? A Doctor's debut is normally character driven with a focus on establishing the new incarnation's personality. Introducing them as the lead in a special where fans will be hoping to see the likes of David Tennant and Matt Smith could rob that actor's opportunity to establish themselves as a definitive version of the Doctor.
The 60th anniversary is the perfect opportunity to remind older fans of what Davies did for Doctor Who and introduce new ones to his incredible style of show running. Better to celebrate what made his era (and others) so popular in the first place before he moves onto the next one.