At first I thought that the game may be challenging to get into for newcomers, but if the flashbacks are done in the right way, it could add a level of intrigue/mystery for new players that may even surpass the original linear story.
I think building some intrigue over how/where the mirror's were found out, the scrolls/leaf, even major characters like ren, guizang or Xiuying being mentioned but not built into an overexplanation of the characters till their reveal would create a new layer of intrigue.
This may be an interesting approach, more than just sprinkling some cutscenes in a fanservice fashion, or some "Oh yeah I remember this stuff" or just context dumps.
What do you guys think or how would you approach this ?