Although I can't believe I'm saying this, each Soul Calibur has had a plausible, yet multi-tiered story which has little continuity problems and decent storytelling. Now what this translates to, is that Soul Calibur, to me, would make a good novel or comic, but not a movie.
Fighting game movies have already had their 3 strikes...
1. Street Fighter
2. Mortal Kombat
3. Dead or Alive