I saw Oz: The Great and Powerful earlier this week with my wife and my 10-year-old son. He liked it a lot, we . . . liked it less than he did.
Oz: The Great and Powerful isn't a bad movie. It's a perfectly fun children's movie that adults can enjoy. But I'm afraid that a prequel to The Wizard of Oz needed to be great, and this movie just isn't.
I'm not going to go all Oz purist and complain that Glinda isn't supposed to be the daughter of the King of Oz, or other details about the setting. L. Frank Baum his own self was perfectly content to cut and paste story elements, make up new stuff, and ignore past continuity. I'm not even going to gripe that the story is set in 1905, which means that the Wizard doesn't even get to Oz until five years after Dorothy's been there. We can assume that the film The Wizard of Oz takes place in its release year of 1939 (and handwave the absence of any post-1900 technology as being due to Dust Bowl era poverty on the part of Uncle Henry and Aunt Em), which gives Oz a quarter-century to age from James Franco into Frank Morgan. These aren't huge problems.
No, the three main problems I had with Oz had to do with odd casting, a big hole in the plot, and technology.
First, the cast. James Franco is okay as the Wizard (though I think the film would have been better with a more energetic wiseacre as the lead actor -- someone like Vince Vaughn or even Steve Carrell would have pumped more energy into the role).
But Mila Kunis as Theodora (the not-yet-Wicked Witch of the West) is completely wrong. Physically she's pretty buxom and curvy, which doesn't really fit the bony, almost skeletal look we associate with the Witch. And for some reason she (and the director) chose to underplay everything. She spends the first half of her time in the movie looking like she's got a sinus headache, and the second half looking like she's got a sinus headache in green makeup. Again, a more energetic, over-the-top actress would have helped.
Second, the plot (spoilers here): there's one big hole in the story. In order to give us a story echo of The Wizard of Oz, there's a sequence in which Evanora (the other Wicked Witch) sends Oz off to defeat Glinda, after telling him she's an evil sorceress and the cause of all the kingdom's problems. But since Evanora is the actual wicked one, this makes no sense at all. I could understand if she sent Oz off to some extremely dangerous place hoping to get rid of him, but sending him straight to the one person who can disprove Evanora's story seems pretty poor planning for the arch-villain of the story.
This may seem like I'm nitpicking, but it's actually pretty significant. Contrast the Wizard's scheme in Wizard of Oz, when he sends Dorothy after the Wicked Witch of the West. He has two problems: a Wicked Witch, and a little girl who can expose his fraudulent nature by asking for help he can't provide. It's pretty callous to send Dorothy after the Witch, but no matter who comes out on top he solves one of his two problems. Evanora's scheme looks the same on paper -- except that Glinda isn't wicked. She's not going to kill Oz if she can possibly help it. Unless Oz is going to snipe at Glinda from long range with a buffalo rifle (which is how I would tackle a powerful sorceress), the odds are good that he's going to learn about Evanora's deception. Evanora should be aware of this.
In other words, the characters are moving around the map because the action setpieces require that they be in certain places, not for any reason that makes sense within the story. That's careless writing.
Finally, the technology: there's too much of it. The movie is jam-packed with eye-popping 3D computer animation. Which means it gets almost tiresome when things keep lunging at the viewer, and the disconnect between the foreground actors and the animated backgrounds is very noticeable. The actors know they're standing in front of a green screen, and it shows. Painted backdrops like those of Wizard would have been more convincing than high-tech super-detailed animation.
Overall, I'd give this movie a gentleman's B+. It's competently made, but never really surprised me or made me wonder what was going to happen next. Younger viewers will enjoy it, but I don't think they'll be enchanted.