Both The Hollywood Reporter and Deadline Hollywood are reporting that G.I. Joe: Retaliation was delayed not only to accommodate box office concerns and set the movie up as 3D for the international market--which was the official reason given by the studio last week--but also to change a major plot point in the film after test audiences complained about a lack of depth to the relationship between two characters.
If you don't want to be spoiled, turn back now. The rest of the article will be drawing from rumors at both sites regarding a major spoiler for G.I. Joe: Retaliation. Because the film is being sent back for reshoots, it's possible--nay, extremely likely--that the plot point in question will change, but in any case you've been warned.
A Paramount executive familiar with the situation reportedly told Deadline last week that at least some of the reshoots that happened before the movie was delayed revolved around Channing Tatum's Duke, who was apparently killed early in the movie. “Channing Tatum had a breakout spring, starring in The Vow and 21 Jump Street. In our first screening of the film the reaction from audiences was good but with 2 big concerns: 1) They didn’t like the fact that Channing and The Rock really didn’t have any time to develop a friendship before Channing died, and 2) Why wasn’t it going to be in 3D? We went back and shot another week with Channing to develop more of his story with The Rock, which made the film play much better. But we didn’t have the time to be in 3D."
There's well-sourced speculation on both sites that as a result of this second round of reshoots, Duke may actually not be killed in the film at all. For those familiar with the G.I. Joe franchise, that may sound a little familiar--in 1987's G.I. Joe: The Movie, the franchise's first feature-length release, the character was intended to die before last-second changes to the script kept him alive. And, like this time, that time around was in deference to the audience; the death of Optimus Prime in Transformers: The Movie in 1986 reportedly sparked a hugely negative reaction among fans and parents, leading Hasbro to reconsider whether they should use what was essentially the same plot beat (the team leader dies while protecting the young upstart) in G.I. Joe.
Obviously, the 3D element has some truth to it, as evidenced by the fact that only overseas 3D screenings have kept John Carter and Battleship from being crippling bombs for their studios (rather than the embarassments they are), and it's widely expected that if Men in Black 3 becomes profitable it will be for that same reason. Still, all evidence points to Channing Tatum's likability as a major cause for the film's delay.