Tomorrowland is director Brad Bird's first misfire, and the problem, I think, is co-writer Damon Lindelof.
From my review in The Washington Times:
At times the movie seems almost comically resistant to providing basic explanatory details: At one point, Athena, who knows practically all the answers, simply conks out when Casey continues asking questions.
The script, which was originated and co-written by "Lost" showrunner Damon Lindelof, relies on the same maddening tricks and obfuscations he repeatedly used on that show: a meandering narrative, multiple important plot threads raised and left dangling, characters who irritatingly refuse to reveal basic information to each other.
Too much of the dialogue consists of grandly suggestive hints about the great wonders and gloomy terrors the future may hold. Every line appears calculated to appear on a startling preview for next week's episode.
The difference here is that "Tomorrowland" is a two-hour film that barrels toward an end, so the inevitable disappointments of the finale come sooner.
It's not all so clunky. Director Brad Bird, the visual miracle worker behind "The Incredibles" and "Ratatouille," works wonders with the movie's smooth visuals, especially in the future-city, and directs the action scenes with a crisp, zippy ingenuity.
His vivid and imaginative work, far more than the frustrating script, consistently captures the sense of joy and awe that the movie seems desperate to evoke.
Lost is only the most prominent example of Lindelof's endlessly irritating shtick. He relies on similar tics and tricks in his scripts for the Alien side-quel Prometheus and the maddeningly empty Star Trek reboot sequel Star Trek Into Darkness, as well as in his current TV series, The Leftovers. His M.O. is pretty much always the same: ask big, interesting questions, and (implicitly) make big, interesting promises—and then take a turn half way through that ignores those questions and promises while treating the audience as either too dumb or too demanding for expecting coherent answers.
There's still a healthy dose of Brad Bird's thematic and visual sensibility, which makes the movie enjoyable in some ways even when it's frustrating. Bird, the director of two genuine Pixar classics, as well as The Iron Giant and the surprisingly excellent Tom Cruise stunt-reel, Mission: Impossible 4, exhibits an enthusiastic fondness for self-starters and high-achieving individualism that has sometimes led to complaints that he's a closet Randian. The Galt's Gulch-esque make-up of Tomorrowland's futuristic society of inventors and artists, who move to another dimension to free themselves of, among other things, government rules and bureaucracy, pretty much ensures that we'll see some of the same complaints brought up here.
But there's ultimately not much to talk about because any specific or interesting ideas that start to arise end up bogged down in Lindelof's vacuous scripting. In the end, the enjoyable Birdisms are swallowed in the void of Lindelofism and don't really work on their own.