@Joan Peter Capaldi's character in Torchwood:Children of Earth was, I think, more tragic than 'not nice' - he had to do something so awful, rounding up children for the aliens, that having done it he went home and killed his family before taking his own life. Capaldi played it magnificently. I think he's going to be terrific. In The Fires of Pompeii he was Caecilius, who bought the Tardis from a street vendor! Incidentally another Who actor (actress really) appeared in that, as a soothsayer; the lovely Karen Gillan - and that turned out well - let's hope it does for Mr Capaldi!