More specifically, it’s been rumored that Tadashi will now be a villain, and the story will revolve around him to a large extent, creating a major conflict between him and other characters. At the same time, the overall tone of the film will be darker and more serious than that of “Big Hero 6”, and the film might be somewhat different in its style as a whole.
This has been worrying to some fans, as one of the reasons the original succeeded so much was its art style and overall presentation. Many fans have been hopeful that the new film is going to keep its art style, perhaps just upgrading it with the use of new technology.
That doesn’t have to contradict the idea of making the plot more serious however, and the original style of “Big Hero 6” could actually add to that, complementing the story that’s being told in the new film. We can only wait and see right now, but we trust that the film’s producers know how to handle this.