Alternatively, the title could be implying that Luke struggled to establish a new Jedi Order. If history has shown us anything, it is that revolutions are relatively easy as everyone is unified against an enemy; it is building a new system which is the real challenge. Look at the French and Russian revolutions or even Egypt right this minute if you dont believe that. Maybe Luke and his Jedi disciples were abandoned after the restoration of the republic, or maybe a new evil reared its ugly head. This would justify the awakening of the Force, empowering an army of Jedi to fight against a newly encroaching evil. This would probably negate the importance of Return of the Jedi (and it would mean that those adorable Ewoks died for nothing.) It would give the film a sense of urgency, and it would certainly mean that Luke, Han and everyone else remains as the underdog in this new set of films.