Regardless of anything else, G.I. Joe = American soldier.
That's out here in real world land.
This is like making a movie about the "Royal Navy" and having it be an international crime-fighting boat squad that happens to have a few Brit members. It's ok if the premise is silly (international crime-fighting boat squad
) as long as you don't have a blatently contradictory title. If you're going to use a real world term, it should logically fit into your premise and you shouldn't change the premise so that it no longer fits.
"Transformers" was still about transforming robots, I think.