We cant place everything on Capaldi, his shoulders will only take so much, and hes a slender chap. Moffat and the writing team need to deliver Peter some meaty scenes to emote his way through. Think Eccleston in Dalek, Tennant in Human Nature/Family Of Blood and Smith in The Doctors Wife. If were to care about the Twelfth Doctor, then he needs to face, to put it mildly, some serious s**t. We know Capaldi is an accomplished and capable actor, so the possibilities here are endless. Apparently the 50th anniversary will send the series into chapter 2 of the Doctors journey, so Im personally expecting some huge and interesting things coming for Twelve and Clara.