I like that they're making it an origin story and not departing too far from the comics. As has been discussed before, if you're going to radically change the characters and story, then just call it something else (looking at you Fantastic Four reboot). I'm with you though - I don't know how casting an Asian person is somehow offensive to the Chinese. This might be a case of Marvel addressing a sensitive issue without really understanding if it's a concern for the audience. There are a dozen ways to have cast an Asian and made things more vague if the concern was really China vs. Tibet.