What they should do is marry the narrative with the sandbox part, but NOT having a fully linear, tightly-structured story, but rather a series of objectives. The world could be semi-open, with new areas opening up once conditions are met.
Instead of being tied playing a specific character, create (or pick) your own. With how hte game is set-up it sounds liek the best option: you crash-land and explore the world to try to survive. Find other survivors and locals, build a base. Make friends or enemies. Bring them in your base/camp or fight them or whatever.
Heck, locations of survivors could even be semi-randomized. Quests they give you too.
Last time I played, you crashland, then 2 minutes later find a camp with everyone inside and just have sex. Actually exploring the island, searching for people, some basic survival would have been nice.