The game needs an ending, I would continue both stories from part 2. Show the fireflies in the new place with new scientists, and Abby joining and helping them out etc. Abby should search for Ellie and after explaining how they can get a cure show a story of them getting back to the fireflies to finally give the game the ending wanted in part 1.
Then also do a prequel of Tommy and Joel joining the fireflies etc etc and eventually separating.
There is so much to do and show on this, it's unreal that they are not doing so.
