By the standards of most vulgar, noisy, relentlessly coarse and stupid children's films, Aardman Animation's first feature-length film built around the stop-motion adventures of bumbling, oh-so-British inventor Wallace and his silent but clever dog, Gromit, looks like sheer genius. But in comparison to earlier Wallace & Gromit shorts (1989's A Grand Day Out
(1989), 1993's The Wrong Trousers
and 1995's A Close Shave
), it's slack and attenuated, with only flashes of the bone-dry wit and goofy ingenuity that make them seem so fresh. Responding to the frenzy of giant-vegetable growing that has gripped their suburban English neighborhood, Wallace (voi...