After watching the main DW DS (3) wanted to watch something else, but I told him we were going to watch Doctor Who Confidential, which was "a programme about Doctor Who". He said "A programme about Doctor Who? Oh, that would be a great thing to watch..." . I don't know where he can be getting it from... I do try to head off any potentially scary bits by describing any monsers as "silly" or "funny" (clearly this simple tactic will avoid years of expensive therapy later).
David Tennant is 6'1", I think, so not precisely short.
I did love the werewolf episode where he puts on an atrocious Scottish accent, mind. That gag alone almost justified losing his normal accent for the rest of the role.