On the blog amcherryfairy, this mother describes how Peter Capaldi went out of his way to talk to a her autistic daughter about Matt Smith's departure from the show. The family just happened to be vacationing in Cardiff and ran into the Series 8 shoot. Apparently-
"when matt smith said he was leaving she was worried, because she goes on adventures with doctor who and Clara and she was worried that the new doctor ( Peter ) would not like her and wouldn't want to join in her games.".During their visit, the family met Jenna Coleman and Samuel Anderson, who told them to come back the following day to meet the Doctor himself, Peter Capaldi.
Hayley Atwell from Agent Carter fame (Captain America's WWII era love interest who founded SHIELD with Howard Stark) just threw her jaunty 1940's hat into the ring to play The Doctor.
Before Peter Capaldi took over as the time traveling alien, there was a growing movement amongst Whovians to find an non-white male actor to play the role. While Capaldi has proved his mettle and has still got some time left in the TARDIS, it doesn't hurt to know Ms. Atwell is hanging in the wings. That is, of course, if Marvel will ever let her not be Peggy Carter.