The Durai Papers were suppressed by the Church at the time. The overarching plot structure is that Orran’s descendant uncovered them centuries later and this is a retelling. I’m sure Orran could have had conversations with Ovelia, but I doubt there would have been much he could have told her that she hadn’t already seen with her own eyes. It’s probably like you said: Delita just couldn’t turn it off. He always struck me as the kind of person that woke up every morning reliving Tietra’s death in his dreams. Going on a successful crusade to wipe out the nobility might have satisfied him at the time, but it wouldn’t bring her back in the end.
As I recall from back in the late 90’s/early 2000’s, the discourse around the ending was largely the same. Plenty of people also thought the two surviving was a bit of an ass-pull. For me personally, it’s one of my favorite JRPGs, but I just pretend the plot ends somewhere in chapter 4. Wiegraf was the game’s best antagonist, and I was never big into the Lucavi plot anyway.