Forget the Disney/Spielberg pedigree: The most important merger in the making of The BFG is the reunion of the director with Melissa Mathison, who wrote the screenplay for 1982's E.T. the Extra-Terrestrial. While The BFG is a faithful adaptation of the 1982 children's book by Roald Dahl, there are decided parallels between Mathison's two scripts, which each hinge on the friendship between a melancholy child and a powerful, benign nonhuman.
Mathison died in November, and while the technical necessities of The BFG are such that the bulk of it must have been finished before her death, Spielberg's film feels weirdly preservationist, as if he didn't wish to change a single one of Mathison's words, even when some quick tweaks would have fixed clunky sequences in its languid first half. It's a sensation similar to the one that came with A.I. Artificial Intelligence—which not only has a title made out of initials, but was similarly based on a mantle Spielberg picked up after the death of its originator, Stanley Kubrick.
As such, The BFG is an oddly paced but eventually rewarding film, with one or two flat-out magnificent stretches. You probably remember Dahl's book as being bubbly and bright, but the English author's humor and fluidity with language disguised a dark tale of Dickensian sorrow and Greek-god violence.