Not going to give up on Capaldi by any means, and I do feel that some of his Doctor's decisions in this episode do have a certain amount of precedent in Tom Baker's occasional callousness-with-a-purpose and the later McCoy's machinations (what I've seen of them, anyway -- still not very versed in his Doctor yet). I also think the fact that 11 spent the last 900 years of his life fighting pretty much every day (thus, in a sense, becoming War Doctor v.2 after all the effort he spent to make War Doctor v.1 just The Doctor again) may have affected how 12 sees the universe, even if he doesn't necessarily like it to.
Still, otherwise, Mrs. Heb and I essentially agree with you, matrix. I'd heard from some people who downloaded the leaked episodes early that they didn't care for this episode, so my expectations were lower going in, but I still feel that the episode didn't hold together. Perhaps the fact that it was co-written by Moffat is revealing -- he may have stepped in to try to make the most out of a weaker episode, or Phil Ford may not have known how to develop what Moffat sketched out. Either way, not so strong.
Also, I note for the second episode in a row that the effects seem to have taken a step backwards towards the Tennant or even Eccleston eras. I can only hope that it's the director (same for both eps so far) or that some of the effects budget is being turned towards recovery/restoration of the much-rumored missing episodes...
I have heard that the next episode is much better, and it looks from the preview like it might be; I hope this is a bump in the road...