I haven't watched the movie yet (of course), but I have watched many trailers available in youtube. I never realize there're actually many bad reviews for this movie.
There's no Mushu and Shang in this life-action. I am sad, but I don't mind it. From the trailers, I think the focus of this movie is 'loyal, brave, and true' so if they add romance it would be a drama and/or tragedy. As for Mushu, I agree that he doesn't portray Chinese dragon as a respected being, especially in ancient time where tradition is very strong.
As for the witch... Yeah, why witch? I think it would be better without her. It's too western (although I don't know if in the movie there will be something that make the witch more asian). But I don't know yet so still 5 stars.
One drawback, I really wish that this movie comes out in Chinese language.