I suspect some of the scenes are still mostly placeholders that will be extended later (fingers crossed). Rather than going with a development path where they fully develop each scene as they go and thus only really allow you to keep replaying the beginning scenes over and over, they added scenes for every stage of the story including the finale so you could actually play through the full game early on.
That leaves lots of openings both for additional scenes in the finale and for potentially filling in a ton of stuff leading up to it. I do think Jess really needs at least 1 full scene devoted to her in the finale soon (preferably with Christine involved in some way), but other than that I think most of what's missing is extensions to the scenes building up to the finale.
Some things I'd like to see: (warning, includes some spoilers)