While nothing has been set in stone, it's expected that the next tale won't follow the path of the original sequel. It can't, since the whole point of that film was to take Daniel and Mr. Miyagi to Japan. Since the remake was already in Japan, it's expected that they'll do the reverse and send Dre and Mr. Han to the United States.
I don't like the sound of that, but we'll see how it works out. I was taken aback by how much I enjoyed The Karate Kid, and am really looking forward to seeing what they do next.