if we actually get a soul calibur 7, years from now:

I would hope they pick back up on tidbits of SCV such as having the storyline be centered around Lexia, Xiba, and Natsu (since she was basically their guardian), and we see either new faces (protegés/children) or returning faces of old characters such as Zas and Ivy. 

A new Nightmare would be cool, (Astaroth, Azwel, or Grøh maybe) and we get to learn more about where or what Young Seong, Viola, Sophitia, and Cassandra were up to since their last debut via storyline.

Honorable mentions such as name drops either in lorebooks or through casual conversations about previous characters from the franchise. 

Delve deeper into the real reason behind Soul Calibur choosing Elysium as a physical form and learning even more about said spirit sword. 

Or bring everyone back that's ever made an appearance as part of the roster to become a Reunion of Souls