Savathun will most likely not be involved directly. I feel that Quira will instead be the character along side Eris that will get character development.
I actually kinda feel the same way. Even though she as a character is kept in the shadows, they would have shown her for marketing purposes if this was [i]her[/i] expansion. She will have her part in this, no doubt, but I would love to see and hear more from Quria.