EDIT: Just saw Roy's Final Smash. While it's still Critical Hit, it's actually not a carbon copy of Marth's Critical Hit, but is actually more different and more...uhm...Roy-like. It's still has the depleting health bar, though.
Actually doing the shakunetsu input changes his neutral special, which is way past cool.
gameplay vids
https://www.youtube.com/watch?v=5_3kI9Ogr68
https://www.youtube.com/watch?v=TWKScE5CqKw
https://www.youtube.com/watch?v=qjB1rs2IHdk