I'm looking at it with the Dynasty Warriors mentality. lol
Dynasty Warriors games have tons of NPCs and characters that with each new entry (which is a reboot/retelling everytime) they declone characters who were either important or a background player that could help supplement and flesh out either the story or other character connections. So it's not a bad idea.
Salia for instance would be a great additional facet to Siegfried's story to tell and be a character this time around to show that there is a character close to him in Schwarzwind that sticks by him (because she loves him) and took over as Schwarzwind's leader in his absence throughout the years he separates from his band. She could be utilized as someone who stubbornly tries to track him down and help him, show him compassion in his suffering, but he adamantly will refuse and be emotionally distant regarding that kind of connection and relationship with someone (which looking at the current canon, he doesn't bother with it probably because he just feels cursed and doesn't want someone else to have to go through what he's had to to any extent of the imagination).
Having and showing someone directly affected by what he's going through/goes through with the Soul Swords, Nightmare and all that in the early part of the story where it all begins for him to that extent in Soul Calibur's story (now being retold) would be an even better alternative take on the storytelling since you'd get to see and know he didn't have to suffer alone, though he chose to. Not wanting to burden people with his pain and everything he had to go through.