It's called marketing. Tom Cruise was BY FAR the biggest start involved, of course he's going to be front and center. Again, it's apples and oranges. Shredder is supposed to be a Japanese martial arts master not a white business man, it's white washing. In Last Samurai not only is Tom Cruise not "the last samurai" he does practically all the learning. He isn't the civilized white man who helps the savages overcome themselves. HE'S THE SAVAGE, they help him overcome his demons, and what they learn from him winds up not helping them "win" in the long run any way. He DOESN'T save the day.
Seriously making comparisons to The Last Samurai is the height of ignorance and would only be made by people who have never seen the movie.