That moment at the end didn't quite work for me. A transition over to Smith's own goodbye to the modern console to close it out would have worked a lot better if their intent was for a 'passing of the torch'/'and it continues to this day' moment. As it is, it kinda just looks like Matt Smith traveled back in time and walked on set.
Really my only complaint about the whole thing. I never would have thought I could enjoy it as much as I did. Well written, well acted, fantastic production values all around and damn near tear-jerking. If Gatiss could bring that level of pathos to the actual show, I say give him the reigns tomorrow.