I've come to this thread late so my comments here relate to things said in posts a few pages back.
I loved Snuff. I have no problem that it is not a comedic book: no one ever said that Sir Terry is only allowed to write comedy. His insights into the human condition are part what I find so special about his books, and there is a great deal of that in Snuff. I like dark books and I think he does them brilliantly. There are humorous leavenings in Snuff, and the footnotes while short and few are still funny.
Vimes' character development, from the drunk in the gutter to the Dukedom thrust on him against his will, and thence to Snuff, set six years after we last see Vimes in Thud, has been excellently portrayed. I would love to see stories covering some of that six years, because at the moment we can only imagine.
In Snuff, Vimes has been a Duke for six years - seven - Sybil discovered she was pregnant just before they went to Uberwald. In that time he must have been learning how to be one while we weren't watching. But... he is not the self-confident aristocrat that some of you have suggested when we see him in Snuff. At the beginning, he is being dragged off from his job to play the part of country squire, and getting him to go is like prising a limpet off a rock. When he gets there, he talks to the staff oblivious of the fact that they view him as their superior, then he wanders down to the village pub and hopes, against all common sense, to be treated like one of the boys. He is disturbed to discover that he is viewed as a privileged toff and wishes he wasn't. He's still the same old Vimes inside, no matter what the trappings of wealth and a title have given him. He uses those trappings to his advantage, but I would not agree that he embraces the position with confidence and comfort. He is always 'wearing his street uniform' under the brocade and red tights.( Actually, I don't think he ever actually got to wear those red tights, he worked very hard to make sure of that.) As he always has, he comes alive when the chase is on. When he finds himself in the middle of the action, just as in all his other stories, he revels in the thrill of it. This is what he was born to do and that is the character trait in Vimes that has run through all his stories. I cannot see why any of you see the Snuff Vimes as a different person than the Vimes that has gone before. He must grow and mature, just as any fictional (and real) person must do, but Vimesness is still there, loud and strong.
On the point of him not being manipulated any more in Snuff, I beg to differ. He is manipulated by Vetinari to be where Vetinari knew there was mischief happening (someone else said that already); he is manipulated by Sybil and the mother of the sisters to give them a lecture on the way they could run their lives; he is manipulated on to the hill to be framed for the murder of the blacksmith. Vimes is not always in control in this book, but when the long fried things are down (sorry Sir T) he grabs control and doesn't let go, as he always has before.
As for leaving his son unprotected in his cabin. That did not happen. Vimes pretended to get drunk to allow Stratford to be more confident, and when Stratford broke into what should have been young Sam's room he found himself jumped on by Vimes senior who had been lying in wait, and the boy somewhere else altogether.
The one thing that puzzles me in the story is the existence of the Summoning Dark in Vimes at all. At the end of Thud, as I understood it, the SD left him, driven out by what called itself the Guarding Dark: the part of Vimes that keeps the Beast at bay. The scar on his wrist was left by the departure of the SD. So to find it still in him in Snuff seems like a continuity error and one I'd like to have explained. Or did I read that part of Thud wrongly?