Sadly, that would require more work than it it seems. The Hinterlands as a game is tied together by the limitation of there only being seven days and some scenes really would break down if you came into them with "impossible variables." To put it concretely, we structured and wrote many scenes with the assurance that some things are impossible to happen in the game, so we didn't have to account for these possibilities and the game could bug out if they happened.
Though as someone who's had to play the Hinterlands more than anyone else, after your first and second playthrough you can breeze through the content you already saw by using the text skip function. Playing through it like that usually only takes a few minutes.
However, I did take notice of how many players would prefer it if they didn't have to restart the whole thing to see more of it. It's too late to apply that to the Hinterlands but if I revisit this mechanic someday in a different game I'll be taking that into account.