He is married to River Song, maybe he’s decided to act the part now that he’s a little more mature.
Fair enough on the cardigan, though I still don’t see a problem with it. 
It was my understanding that Crombie started making their 3/4 length coats in the early 1900s, but they made it into popular culture in the 1960s/70s. But, given the doc martens, I’m going to go with mod-inspired.
BTW, this guy is the absolute master of Doctor Who fashion, and specializes in identifying original costume components. He has separate blogs for each Doctor’s costume he recreates for cosplay and goes to absurd lengths in identifying the exact items used by the BBC in creating their original costumes. As I guessed, he’s already identified the jacket as a custom job from Crombie modifying this item, and identified the shoes as not Doc Marten’s but these ones from a company called Laoke.
I expect him to have the cardigan identified in no time.
ETA: I guessed that he’d have identified the jacket, not which one it was. I’m no fashionista!
^^Sweet. Have to say, I do like the red lining though!
Me too. Not sure about the DMs though. Is he going to give the Daleks a good kicking?
Plus I never trust anyone whose shoes are that shiny. It’s not natural.
I bet he was hoping the Doctor would have been played by Michael Sheen.
The costume’s fine.
The pose is ridiculous.
More (unofficial) pictures sneakily taken from the set. Potentially spoiler-ish, I suppose, though there’s no real way to know what they’re saying.
As predicted, it looks better in use than in that ridiculous pose that seems designed to emphasize everything wrong with the costume. Still not a big fan of it, but I don’t think it’ll be a distraction.
And sure enough, Steve Ricks has the cardigan identified. It looks like he had that posted when I first linked to his site, in fact, but I swear that wasn’t the case. Ugly sweater, in any event. Especially for the price!
Yeah. The pose, plus only seeing the top half at first, made me think he was going to go fight “You-Know-Who” with a red head and a smart girl.
Already a thing on Facebook comparing it to Doctor Orpheus (from The Venture Bros).
What no bow tie? But bow ties are cool! Actually I hated bow ties until Matt Smith’s doctor. Am looking forward to seeing the new dr & the costume come to life.
I though 11 was simply channeling his inner Bill Nye.
Ooh, perhaps Matt Smith will pop over here and debate Ken Ham. 
I agree with the posts above saying that the costume’s good, but the pose is awful. The outfit suits Capaldi; it also distinguishes him from the others, which is a good thing. When I watched a few seconds of that show that first introduced him as the new Doctor, he looked a bit too much like Tennant to me (not that Tennant wasn’t awesome - but I think it’s best to try to build a new look with each Doctor).
I think he struck that pose on purpose…remember when I said they seemed to be drawing parallels to the Third?