Why Colin Salmon oughta be a future Doctor
Here’s Colin Salmon as Dr Moon- as you probably remember, he was the ‘virus checker’ for the Library. He’s part of the computer River ends up in. BUT! What if he’s also the Doctor?
Let’s say that after a long life of fun and adventure, the Doctor goes to the Library planet, long before River gets there. He uploads himself into the computer, replacing the original Dr Moon (which is merely a computer code and wouldn’t mind). He hangs out with CAL and later Donna (whom he is delighted to see) before River arrives…
When River arrives, he’s there to greet her. River reunites with her teammates and then…THEN…the Doctor asks “River, don’t you recognise me?” River looks into the eyes of the man she knows as Dr Moon and realises he’s the Doctor, her husband. They tearfully reunite.
River now has the man she loves and a whole new world of her own- sometimes she reads to the children, sometimes she reads for herself, sometimes she parties solo, and sometimes she goes on adventures with the Doctor just like she used to. Happy endings all round!
And for a bonus happy ending: Amy and Rory made a prior arrangement with the Doctor to be uploaded into the Library after their deaths. Since this is a computer world where apparently anything goes, Amy and Rory finally get to raise their baby, while adult River gets to simultaneously have her life.
They all live happily ever after! The end.