Back in 1996, a novel was released which filled in some of the gaps between The Empire Strikes Back and Return of the Jedi, but the big difference with Shadows of the Empire was that it was treated like one of the movies, with merchandising and a huge amount of promotion surrounding its release. However, it turns out that Star Wars: The Force Awakens very nearly borrowed this title from the now no longer canon novel as Pablo Hidalgo (Lucasfilm's creative executive and its "in-house Star Wars geek") has revealed the following on Twitter about early plans for the movie:
Whether this was actually going to be the title or was just a placeholder is hard to say, but it definitely would have been a fitting alternative to The Force Awakens seeing as the shadow of the Empire definitely loomed large over the events of this movie. Which do you think is better though?