Remember the scene where JGL is trying to escape out of his apartment, and starts falling off the fire escape, when the movie suddenly cuts away to showing the "original timeline" for Joe, covering the 30 year timeframe in fastforward?
At that moment, I thought that what the movie was going to do was show the timeline play out over and over several times through the rest of the film, but each time around you'd see how the events from one loop introduce a change into the next loop to make it different, until there's some kind of stable equilibrium or something at the end. (Which I guess would make it sort of like Groundhog Day or something, but played out over 30 years rather than one day.) That would have been a cool concept. Better than the one way actually got in the movie (IMHO).