“A Wrinkle in Time” wrinkles the plot and fails to iron it out.

I agree (as far as I can tell) with what you’ve written here, but I’ve only read excerpts and summaries of the novel, so I’m not authoritative.

I suspect the themes of the novel were updated to reflect our current social neurosis, in particular Ava DuVernay’s neurosis. I came away from the film thinking Meg’s lesson was mixed race features are OK, and Oprah’s character was all about convincing overweight people to love their weight. The film’s theme seems to be all about inclusion, not so the novel.