I stopped at Soulcalibur III, and apparently nothing has changed in terms of movements, which I managed to do very well again.
There are some modes in the game like Soul Chronicle where it explains better the story surrounding this franchise, Libra of Soul where the player can create his own character, in which he can do side quests, beyond the main quests, hire mercenaries, buy better weapons and items, etc. where each mission has there conditions to win, and this all happens in a common time span with the other characters, which is cool.
Not forgetting this Soulcalibur has some new characters to play and the player can challenge other players online.
Perhaps the only thing I found negative in the game is the lack of varied items to to create a character. But it is still an interesting game to play.