Today some Force Awakens action figures got leaked online. The backs of the cards have so far only shown one new alien, but what interested me is that Luke in his Cloud City outfit is included in the line. There were previous mentions of Darth Vader alao being included in the line.

I'm taking this information to assume there will be a flashback to Cloud City in the movie and the lightsaber Luke lost there really is some key plotline. Not a good plot to pursue, IMO, but its looking more likely now.