9. Geoffrey Bayldon
When casting the very first Doctor, several actors were approached before choosing William Hartnell. Among these actors was Geoffrey Bayldon who reportedly turned down the role because he didn't want to play such an old character. Ironically he then went on to play the wizard Catweazle, an old wizard thrown out of his time. He was supposedly approached again for the role of the Second Doctor, but once again turned the part down. Bayldon's Doctor, if anything like Catweazle, would be the epitome of a "mad man with a box." Dressed in shabby garb and eccentric to the point of insanity, his in-the-moment plans would frequently go awry leaving viewers to wonder whether his companions could handle these adventures better without him. He'd be out of touch (even more than the average Doctor) and difficult to take orders from due to his ragged appearance. A Doctor who's infinite wisdom is lost among the thoughts of a mad man.