Alright, so the pure historical may be a lost relic, never again to return to Doctor Who. Although undeniably interesting (and occasionally educational), the powers that be think that there needs to be some science fiction or fantasy element to the story for it to be proper Doctor Who, and a lot of viewers agree with them. But I don't think that the psuedo-historicals are going away anytime soon, and while they're still around, we have the opportunity to meet any number of historical figures. It's fascinating to think of how the Doctor could get mixed up in the lives of people who have dramatically impacted history. When dealing with biographies that have been closely studied, we can pick out the points at which the Doctor could have gotten involved. In the case of Agatha Christie, it was the explanation for her mysterious disappearance. With Vincent van Gogh, it was the opportunity to see the impact he would have on society. But there's so many more historical figures out there, some of them seemingly tailor made for Doctor Who. So instead of setting yet another story in present day London, I humbly suggest the following to appear on the show.
10. Rasputin
I have no doubt in my mind that Rasputin was, in fact, an evil alien hellbent on chaos and destruction. Let's look at the evidence, shall we? He cozied up to the Romanovs, gaining unheard of influence to the point that he had an almost hypnotic effect on the Tsarina. His presence at court directly coincided with the Romanovs increasing unpopularity with the Russian populace and the February Revolution of 1917, which saw the family imprisoned and eventually assassinated. Although reports of his murder are embellished, he allegedly died only after being stabbed, poisoned, strangled, shot once through the chest and once in the forehead, clubbed, and finally thrown in an icy river with weights tied to him. Plus, there's those eyes. Those are not human eyes. So if Rasputin is an alien on Earth, obviously the Doctor's going to end up meeting with him sooner or later. Maybe he's a Timelord (now that the Timelords are being brought back), and the Doctor has to convince him to leave the planet before he causes any more trouble. Maybe this is how we finally bring back the Meddling Monk! He was known for getting all embroiled in major historical events, and the Doctor did leave him stranded in 11th Century England. Maybe this is just him a few regenerations down the line, after being driven mad by boredom.