And the Doctor is 900 years old.
Actually it's over 1100 years old if you are to believe the line from the first episode of last series that he was over 1100 years old just before he got shot.
As far as arguing over having more doctors or more former companions. It would be real easy to get a convoluted story with too many people in it. So I would understand a few relatively recent companions and 2 doctors and nods to the past doctors instead. A more expansive reunion story is something that Big Finish can do and they have proven to do those fairly well in their format.
But even in the classic format it was hard to really do good reunion stories. The only one that really worked well was the Three Doctors which was really only 2 doctors. Even the 5 Doctors was really only 3 of them with a ton of padding.