In fairness, whilst 11 showed no signs of despising soldiers, 10 had a pretty prominent disliking of weaponry and combat as well. It disappeared during Matt Smith's run but seems to be making a comeback now. If we want to interpret character motivations, then perhaps we could postulate that 10 grew to hate all things that involve killing and became "The man who never would" (a dumb term) because of his PTSD from the Time War. 11 would then completely do away with this character trait because The Doctor was regressing into a more naive and child-like form of himself to escape the pain of what he did. Then came the events of The Day of the Doctor and the Doctor's actions were mostly reverted. He was saved of his guilt and later became 12, who after his time on Trenzalore was sick of fighting and war and combat, and grew to hate all things soldiers. I'm not going to pretend that it does seem fairly out of left field but I can see where the writers are coming from on this one. Points B, C, and D are completely legitimate. They're some of my biggest problems with the series right now. I won't even bother addressing those since you already did a pretty good job. Because he is. That happens when the Doctor regenerates. Not only his appearance, but also his entire personality and his outlook on life changes. When 8 was dying, he wanted to become a warrior and so he had that wish granted, completely doing away with his prior fears of guilt over combat. 10 was well versed in human culture and would even reference our media from a major movie such as The Lion King, to an evening-time soap opera such as Eastenders. Compare this with 11 who thought that football was "the one with the sticks" and had a strong disliking of the taste of alcohol. I'd say the Doctor changes because with each regeneration comes different priorities in his 2,000 year old mind. From 12's "planet of the pudding brains" comment it's obvious that he doesn't hold humanity in as high a regard as his predecessor 10, which is fairly acceptable given he's, as we've already said, 2,000 years old. He's busy adventuring and doing equations on his chalk board so it's obvious that his mind is elsewhere when it comes to social norms he was once aware of. Most of the time when he "insults" Clara, he never shows any intention of doing so. He seems his same old scatterbrained self that he's always been and I think that's fine. Again, consider the situation. He doesn't have to be nice to her. He's just had his entire reality shattered by the knowledge of other worlds teeming with life. He was nearly killed a few minutes prior, and now his girlfriend has revealed that she's living a double life in which she encounters that kind of situation on a daily basis. I find your desire for him to be calm, measured and practical to be a little unrealistic. Also that last comment was your interpretation so I probably won't say anything on that. The episode was mainly written by Gareth Roberts. No association with Sherlock.