It's my belief that the movie should be written as an 'action-military' story. THEN put GI Joe in there. I'm thinking particularly of something like THE ROCK. Sure, the Sean Connery element wouldn't work, but uh, you get the idea. NAVY SEALS was another example. Story first and then tweak it so it caters to certain GI Joe characters. But man, don't write it around a character (like Matrix).