Rowling's first novel for adults is the story of a small British town that has mostly kept a lid on the conflicts that simmer among its citizens. But when a member of the Town Council dies, and an election is called for his replacement, all that simmering tension comes bursting to the surface, and little Pagford is thrown into turmoil.
There are about twenty principal characters here, which is too many; Rowling doesn't have time to give any of them more than one or two quickly sketched character traits. Her adolescent characters are, if anything, better developed and more rounded than their parents; perhaps all those years of writing teenaged characters in the Harry Potter books helped.
Even worse than their flimsiness, though, is their loathsomeness. There's not a single admirable character to be found; they are all small, petty, mean people. It's as if Rowling somehow got the impression that yeah, all that stuff about the kids and magic was nice, but what we really wanted was a book about a village full of Dursleys. It's true that loathesome people can make for good entertainment, but Rowling isn't going for the sort of dark comedy in which she might get away with that. The Casual Vacancy is intended as amiable, light drama with the occasional heartwarming smile, and that requires at least one character we'd like to spend time with.
The plot's not much better than the characters. The first time a council campaign is sabotaged by a family member, it's mildly amusing, but when it happens a second time, and a third, in precisely the same way, that's too implausible a coincidence to hold up. And after 450 pages of light village banter, the final 50 pages aim for a tragic ending that doesn't work and isn't earned, mostly because the character around whose death it's built has been little more than a prop to that point, and we've been given no reason to care about his fate.
Even in its very best moments -- there's an extended sequence at a birthday party that works well -- The Casual Vacancy is never more than mildly interesting, and those very best moments are few and far between.
Harry Potter 8, please?