We know Vader is in it. We know they're testing the Death Star. We know the rebels are after the plans, and ultimately they get them.
It's a very similar situation to Revenge of the Sith - what follows the movie we're about to watch has been established, fates are sealed in most cases, outcomes are or should be easily predictable.
But the big question is the execution. I know generally people scoff at novels, but sometimes they add extra depth. Dark Lord: The Rise of Darth Vader added interesting details to the story that played out in the Star Wars: The Force Unleashed video game. In a